Across The Divide: Diamond Distance!

Yesterday was my sixth attempt to complete a Diamond Distance task.  The basic requirement is a pre-declared 500km task with up to three turn-points.  My strategy for setting these types of tasks has improved over time.  I now adhere to the following principles:

  1. Select a task area that provides the best soaring weather over the course of the day.  Some parts of the task area might work best in the morning and other parts might work best in the afternoon. Thermal height and depth, thermal strength, convergence lines, development of cumulus clouds, over-development risk, wind direction and speed at different altitudes, buoyancy/shear – all of these things matter, and I try to account for all of these factors.  I predominantly rely on Skysight for providing the forecast because it makes it easy to examine all factors for the entire task area throughout the day.
  2. Place the first and second turn point furthest away from Boulder and place the third turn-point closer to home such that the last part of the flight can be flown within glide range of Boulder.   This drastically reduces the likelihood of having to land out when the day might die towards the end.
  3. Pick accessible turn-points.  I.e., avoid turn points that might be difficult to reach, such as high mountain peaks.  Each turn point should also be in an area of forecast lift at the approximate time or rounding it.
  4. Ensure accessible landing places along each task leg.  The spacing of these is most critical early and late in the day.  The part of the task that lies during the best part of the soaring day (approx. between 1pm to 4pm) can be the most challenging.

Yesterday’s task adhered to these principles.

The task line is shown in blue and the turn points are marked in red by 45 degree sectors.
  1. The Start point was at Nugget Ridge as I planned to take a northwest tow and Nugget Ridge is right on the typical tow route in the morning.  Putting the start to the north while my first TP was in the south would also ensure that I would be in close proximity to the airport as I would try to get underway.  Thanks to Pedja Bogdanovich for this tip!
  2. I set my first TP at Woodland Park, a few miles north of Pikes Peak.  Skysight forecast a convergence line to the south in the morning along the foothills, and the first cumuli were projected along that line.  Cloud bases – which were generally a bit lower than I liked – were forecast to be higher to the south than to the north.  Also, the south was projected to be less windy.  (Strong winds can shear off the thermals, making it harder to climb.) Perry Park was my go-to landing spot on the southbound leg.
  3. My second TP was at Toponas, due west of Boulder.  This would make for a challenging second leg across some difficult terrain but the route was supported by the forecast and my fall back plan was to go back north along the convergence before heading west. Potential landing spots were Perry Park, Henderson Ranch (in the nw corner of South Park – thanks to Tom Z), some fields north of Silverthorne, the airport in Kremmling, as well as some fields near Toponas. While the second leg was the longest, it would not increase my distance from Boulder.
  4. My third TP was Squaw Mountain, located south of Idaho Springs on the ridge that extends from Mt. Evans towards the northeast. I have often found lift in this area even in west wind conditions (however, you do not want to get any closer to Mt. Evans on the lee side on west wind days).  Kremmling and Granby would be easy-to-reach landing spots west of the divide on this leg should a land out become inevitable. Squaw Mountain is already relatively close to Boulder and 13k feet would put me in glide range.
  5. I set my Finish at Kenny Mountain, east of the Twin Sisters.  This ensured that my entire last leg could be flown within glide range of Boulder.  (I would have to round Kenny at 11k+ feet to have Boulder in final glide. Having the finish point away from the airport (but within final glide) has the side benefit that rounding it would invariably ensure compliance with SSA rules for Diamond Distance tasks. These rules require that the finish altitude is not more than 1000m below start altitude.)

Total task distance was 312.1 miles or 502.2 km (plus the final return to Boulder).

First Leg

Fortunately the day started early and there was no need for a big mountain tow.  I took off at 11:12 am, released at 11:21 and flew across the Start line at 11:30, at an altitude of 11,000 feet.

Having my first leg pass the airport meant I could get going on course without first having to climb up high.

I released right above the entrance to Left Hand Canyon. After a few turns I flew across the Start Line on Nugget Ridge and headed out south.

There was good lift along much of the first leg even though I chose to fly in thermals several miles west of the convergence line because the cloud bases were significantly higher than along the convergence.  Following the convergence might have been a bit faster but keeping a good altitude was more important to me along this stretch because there are very few landing options and the only good one is the private airfield of Perry Park.

It was nice having (unplanned) company on this first leg.  5K was heading to Pikes Peak and both of us left Boulder at about the same time.  Flying side by side at times helped to see as to who had the better line.

My flight trace is shown in red. 5K is shown in light blue. We parted ways south of Deckers when I left the lift line to round my turn point at Woodland Park while 5K stopped to climb, heading to Pikes Peak.

I averaged 81kph on this 128 km leg and rounded Woodland Park at 12:56pm.

Turning Woodland Park.

Second Leg

Looking ahead after turning Woodland Park the second leg seemed daunting.  The distance to Toponas was almost 200 km, much of it across challenging terrain and tall mountains.  The cloud bases were still relatively low, around 16,000 feet.  This may seem quite high for those used to flying at lower altitudes, but it really isn’t when considering that much of my direct route ahead led over unlandable terrain between 10,000 and 13,000 feet.

The area north of Woodland Park is a bit lower but that makes it all the more insidious.  There are no places to land and there is an elevated ridge to the east (and to the west).  It is imperative to maintain an altitude that allows clearing the eastern ridge to glide out to Perry Park.  The further west one flies, the higher one has to be.  I scared myself once before in this area and was determined not to let it happen again.

This screenshot captures my flight trace north of Deckers as I am trying to stay on course. You may notice my erratic-looking flight trace with a hook to the right (east) at the top. The ridge to the east is between 9000 and 10000 feet tall and being able to clear it at all times is essential to staying safe. You can see why following the course line takes you further away from the plains and requires additional altitude. My altitude dropped below 14,000 and in response I turned east to get closer to the plains. This is why cloud bases of 16,000 in this area should be considered relatively “low”.

I quickly found some good climbs back to cloud base and got myself back on course, passing Mount Evans on the west side.

Passing Mt. Evans and heading towards Silverthorne (Evans is the tall mountain to the right of the flight trace. Silverthorne lies in the valley ahead.)  It is easy to see that cloud bases of 16k are uncomfortably low in this area.

Unfortunately, the cloud bases had still not risen much beyond 16k feet.  I made it to the ridge south of Keystone Mountain and then stopped, milling around in middling lift unsure what to do.  There were some clouds ahead but they did not look reliable. I could definitely glide ahead towards Silverthorne but I was concerned that I might get stuck in the valley.

Circling near Keystone Mountain east of Breckenridge. The western flank of Mount Evans is center right in the background. A glimpse of the Flatirons, 45 miles away, is visible on the horizon in the distance on the left.

I also wondered about the impact that Dillon Reservoir would have on the thermals.  Ironically, the best looking cloud seemed to be right above the lake.  I was not willing to trust it.  There was a 12-16kt southwesterly wind at my altitude so I figured I might be able to ridge soar along the south-west facing slopes of the Ptarmigan Range north of Silverthorne if I could get there close to the top of the ridge line.  Which seemed possible, although by no means certain.  I also considered the potential impact of Eagle’s Nest Ridge, upwind of the Ptarmigan Range.  This ridge was even higher and I figured it might mess with the wind direction.  It could also mean lee side turbulence and sink.  The more I thought about it, the more uncomfortable I became.

Dillon Reservoir is in the upper left. The valley beyond the reservoir in the distance leads directly to Kremmling.

So after a lot of hesitation, evaluation, and considering my options, caution prevailed and I decided to return to the east of the Front Range.  I remembered what I learned in Austria: when flying in big mountains, especially ones that one is not intimately familiar with, it is always best to stay well above the ridges.  I was not certain that I could do that.  Maybe cloud bases of 16k were simply not enough for my first trip to the west…

Returning to the Front Range. Georgetown along I-70 is in the valley below. The Front Range is straight ahead. Longs Peak is visible in the distance.

I crossed over Mt Bierstadt and Mount Evans, heading north towards the Divide.  Just before I got to Winter Park, I spotted my opportunity: a line of clouds had developed in westerly direction.  I had just climbed to almost 17,000 ft, i.e., cloud bases were finally rising.  The airport of Granby was within glide range.  No mountain ridges were in the way.  I had wasted some time but it was still early enough in the day.  There were no more excuses. And with that I resolved to jump to the west.

The moment I decided to make the jump to the west. The divide is still a few miles ahead. Granby is at the bottom of the valley towards the right.

Crossing the Divide was a big moment.  It felt daunting and liberating at the same time with the former gradually giving way to the latter.  I reached full acceptance once the distance to the divide had increased to the point where gliding right back was no longer possible without gaining altitude first.  At that point I just focused on one thing: progressing forward and not run out of time.

Whenever you fly over new terrain your inclination – rightfully so – is to stay high.  But staying high also comes at the cost of being somewhat slow.  Centering thermals takes time. Centering and climbing in weak thermals takes even more time.  Centering and climbing in weak thermals while going into a headwind is even worse.  I was wondering: how high is the working band?  How low can I afford to get without having to spend even more time digging myself out.  These were questions that had no answers for me.  So whenever I found reasonable-seeming lift I turned at least to test it.

Fortunately the terrain between the Divide and Kremmling looks a lot more hospitable than the terrain over the foothills.  If the clouds are high enough you can easily keep an airport (first Granby, then Kremmling) in glide.  And even in the worst case of hitting massive sink – which actually seems a lot less likely given that the terrain is more mellow – there are often some farmers’ fields around where putting the glider down safely seems possible.

I managed to stay high enough to never get out of glide range of an airport.  This saved me a lot of stress albeit at the cost of speed.  One hour after crossing the Divide I finally got my turn point in view, still 15 miles away.  I had expected a little town but all I could make out from the distance was a road intersection.

The immediate issue at hand was that I had almost reached the end of the clouds before a significant blue hole above the lower terrain to the west.  I tried each of the last remaining three little clouds and finally found a good climb to cloud base under the last one allowing me to head out into the blue, round the turn point and stay within easy glide of Kremmling the whole time.

Rounding Toponas

I rounded Toponas at 4:16 PM.  The Divide looked very far away.  But the sky ahead looked great, considerably better than on the outbound leg.  I was hoping it would stay this way for a while for I had a lot of ground to cover.  Looking at the clouds I was pondering which of the two most promising lines to take.

A few minutes after rounding Toponas. Very nice looking clouds beckon ahead, promising quick progress on the return. Kremmling (not visible) is in the valley beyond the hills in the foreground. The Continental Divide is far away, barely visible on the horizon.

The southerly line (the one to the right of the nose in the picture above) was better aligned with my 3rd turn point but it would keep me on the west side of the Divide for longer. The northerly line (the one to the left of the nose) went directly towards Granby and the nearest point on the Divide.   My number one goal at this point was to make it back over the Divide, my number two goal was to complete my task.  I chose the northerly line.

The town of Kremmling is below, surrounding the airport. The Divide is now better visible on the horizon. The scenery was just beautiful.

A dark flat-bottomed cloud slightly north of Kremmling promised compelling lift. I figured it would be worthy of a small detour.

The cloud that promised delivered. If every climb had been like this, I would have been around the course in half the time!

Thanks to lift like this and the wind in my back, progress on the return was blazingly fast. Even despite little mistakes like the one in the picture below.

As I followed the line in front I could readily see that the cloud straight ahead was decaying. I should have detoured around it via the cloud to it’s right. Instead I held course and was rewarded with substantial sink under the dying cumulus.

Only 40 minutes after rounding Toponas I was already approaching the Continental Divide.

Close to cloud base it is often not easy to see the direction of the cloud streets. But the cloud shadows can be a dead giveaway like in this prime example. It was easy to see which way would get me over the Divide the fastest.
The town of Granby and the airport are below on the right. Lake Granby features prominently in the center. Longs Peak is towering right behind.

These clouds were the best of the day.  I barely had to stop for a circle or two. Most of the time I could just dolphin up in lift and then drop the nose to bridge the short gap to the next cloud.

Beautiful view of the Divide from the west in late afternoon sunshine. Longs Peak is on the horizon to the left.

Approaching the Divide was a non-event and although it was already 5:15 pm, the day was still looking great.  Now my mind could start to focus on something else: was it still possible to complete the task?  I had another 110 kilometers to go.

A big blue hole greeted me as I crossed the Divide via Mt. Neva.  The air on the east was very turbulent and I hit massive lee-side sink.  I pushed the nose down, accelerated to 90+ kts and headed straight to the nearest spot along a long cloud street that seemed to stretch from Longmont towards Berthoud Pass but then turned away from the Divide towards Idaho Springs and continued in south easterly direction beyond.

As I approached the line I could readily see that it was generated by a convergence of different air masses.  I connected with the line southwest of Rollinsville and immediately found myself in strong lift.  After a few turns in turbulent rising air I continued southbound along the line.

This line seemed like a present from the powers to be: it was perfectly aligned to curve around towards my third turn point at Squaw Mountain.

Rounding Squaw Mountain, my third turn point.

I turned Squaw Mountain at 5:33 pm with another 70 kilometers to go to the Finish at Kenny Mountain.

Instead of heading straight to my goal in the north, I backtracked along the line I had just come from.  This required an almost 40 degree deviation from the direct course line (see flight trace above) but it was most certainly the fastest route.

Without a single turn I continued to climb along the line, which allowed me to make rapid progress.

Cruising in straight flight along the powerful convergence line. Here I am on the final (northbound) leg south-west of Nederland. Barker Reservoir is about 8 miles ahead 15 degrees to the right of the nose.

I continued in straight flight along the line until I reached 16,000 feet near Gross Reservoir. I had 35 kilometers to go to my Finish Point at Kenny Mountain and from there another 20 kilometers to get back to Boulder.  Barring some extreme sink event, I had more than enough altitude to complete the rest of my flight in a single glide and arrive back in Boulder with height to spare.

Flying past the Indian Peaks as the evening sun breaks through decaying cumulus clouds while I head north towards my finish point.

I told myself that it was still too early to get excited.  My route would take me into the lee of the Twin Sisters.  I still could not be certain.

Approaching Kenny Mountain – part of the rocky area right below the nose. Estes Park is further ahead.

The big sink did not come.  At 3 minutes past 6pm I rounded my Finish Point with an altitude of 12,000 feet – 1,000 feet above my start altitude, and 1,500 feet higher than I needed to safely make it back to Boulder.  It was a great moment.

Rounding Kenny Mountain: the 500km task is complete.

After five failed attempts, I finally had made my 500 km Diamond Distance.  And it was in good style with my first excursion to the west of the Continental Divide.

There was still some lift as I’m returning to Boulder.

I hit a good line on the return to Boulder and had enough altitude to spare for a celebratory fly-by of the Flatirons before returning to the airport where I landed at 6:24 pm after 7 hours and 12 minutes in the air (my longest flight duration thus far).

My OLC flight distance based on optimized six legs was 564 km with an embedded FAI triangle of 439 km (also my biggest yet).  One day later I also noticed that the flight was the highest scoring flight for the day worldwide with 651 points on OLC plus.  The flight track is here.

Unexpectedly, my flight turned out to be the highest scoring flight for the day on OLC Plus worldwide. Granted it was a weekday with far reduced competition and I clearly benefited from outstanding soaring weather.

Lessons Learned

  • Don’t Give Up.  It took me six attempts to make Diamond Distance.  It’s eminently doable without taking any risks but it requires a really good day and a bit of luck. (My bit of luck was the perfectly aligned convergence line at the end of the day that allowed me to cruise to TP 3 and the Finish without turning.)
  • Yay to the West. The Continental Divide can be intimidating because it can get in your way on the return to Boulder.  But flying in the west certainly isn’t any harder than it is in the east. And the terrain towards Kremmling is much more hospitable with better landing options and good low-traffic airports within easy reach. If you pick the right day – you want high cloud bases, good thermals, modest winds, and a low risk of over-development – then you’re set for a lot of flying fun.
  • The Height of the Cloud Bases Matters a Lot. Obviously this isn’t a new lesson but this flight really drove it home.  You must always factor this into your flight planning.
  • Stay Above the Ridges.  This is one of the main principles of early mountain flying that I was taught in Austria. Thermal lift is almost always best above the ridge lines.  Ridge lift will work best at ridge top level but you have to be sure about the strength and direction of the wind.  This is not a given because often the wind aligns with the direction of the valleys looking for the path of least resistance. Being on top of the ridges also gives you the best view, the smallest chance to get lost, and the widest choice of thermals to pick from.  So in short, especially when flying across unfamiliar terrain, it is always best to stay well above the ridges.
  • Carefully Examine the Forecast for Good Lines and Select Lines Over Hospitable Terrain.  Skysight correctly predicted the energy line to the west across Granby, Kremmling, and beyond.  The line extended much further than I could even see.  I’m pretty sure I could have kept going west for another 50 to 100 miles. (I just would have run out of day coming back).  Lines that run over landable terrain with good airports are the best!  The easiest starting point to find good energy lines in Skysight is by looking at projected XC speeds throughout the soaring day.  This combines the forecast for thermal and convergence lift. You will then want to validate your choice by looking at cloud bases, thermal strength and a low Buoyancy/Shear ratio (indicated by “stipple” on the thermal strength chart).
  • My Flight Planning Strategy Worked (summarized at the beginning of this post). After five failed attempts I had learned from prior mistakes.  If you plan your first long flights I recommend you adopt a similar approach to planning your route.
  • Fly Around Decaying Clouds. Expect to find sink underneath. A slight detour can be a better option, especially one that takes you across an actively developing cumulus.
  • Cloud Shadows Indicate Clouds Streets. When flying close to cloud base it can be impossible to see the direction of the street ahead.  But the shadows on the ground are a great marker.
  • More Field Walking Is Required.  On my next drive out west along I-70 I will want to check out a few fields north of Silverthorne.  It was tempting to try soaring the ridge along the Ptarmigan Mountain but without having seen the fields at the bottom of that valley this was clearly a no-no.  (I have researched several fields in this area via Google Maps but my degree of confidence in a field improves hugely after seeing it on the ground.)
  • How Do I Determine the Height of the Working Band?  I could have flown much faster, especially on my leg to the west into the headwind, had I been more choosey about the thermals I picked.  But this would have meant being comfortable getting lower before picking a thermal to climb in.  Without experience in the area that I was flying in, I had no idea how low I could let myself get before having to worry about climbing back up.  I still don’t know.  If you have any tips, please let me know!


When 13k Is Too Low

I’ve had a few days to ponder another failed Diamond Distance attempt on August 6 and reflect on what prompted me to abandon my task very early on a promising looking day.

The weather forecast was strong, particularly to the northwest, and I had set an ambitious task with the first turn point at Bridger Peak, 40 miles south of Rawlins WY, and halfway between the airports of Saratoga, WY and Dixon, WY.  To get there I would have to cross the Continental Divide into North Park, fly across North Park and then continue along the next mountain range to the northwest.  The direct air distance from Boulder is 125 miles.  The road distance is more than twice that, and driving there takes about 5 1/2 hours.

Declared Task. The turn point on the upper left is Bridger Peak.

I had a good and early start after releasing from tow south of Coal Creek Canyon (between Boulder and Golden).  I then climbed to 16,000 feet over the Flatirons, quickly crossed my start line and headed in north-westerly direction.  It was still early in the day with few clouds.  My immediate objective was to find a good spot to climb up to the Divide and then cross it at a location that would give me a safe passage into North Park.  The best area for that seemed to be northwest of Estes Park.

A few miles to the east of the Twin Sisters I found a strong 6-7 kt climb to cloud base at 16,400 ft and headed west from there towards the Divide.  Although the cloud bases were still relatively low, my last few climbs had been good and I felt fairly confident that I would find good lift as soon as I would reach the Divide.  So far everything had been quite easy.

East of the Twin Sisters I found a strong climb that took me to cloud base at 16,400. This seemed sufficient to approach the divide. I was hoping for additional lift above the Twin Sisters and along the northern flank of Mt. Meeker and Longs Peak.

That’s when my troubles began.  The 12 mile push through the lee cost me more altitude than I had expected and when I reached the Divide above Flattop Mountain my altitude had dropped by more than 3,000 feet.  I was down to 13,200, which put me at only 900 feet above the ridge.  I remember thinking, “there has to be a climb here” and, “what do I do if there isn’t”?

Flight track approaching the Divide. On this 12 miles stretch above high terrain I expected good air but only found sink. The glider icon is above Flattop Mountain, directly at the Divide, at 13,000 feet – 3,400 feet lower than I had been just 10 minutes earlier.

The airport of Granby was in glide range. But the conditions in the Granby Valley, which I could now see for the first time, looked unsoarable and cloud bases there were very low, probably well below 12,000 feet.  I felt almost certain that diverting towards Granby would mean accepting a retrieve.

3D screen shot from the same position over Flattop Mountain at 13,000 MSL (900 ft AGL), looking towards Grand Lake and Lake Granby. Granby Airport is at 8,200 feet MSL – a fairly safe looking glide from this position (20 miles away). 

The direction towards North Park looked much better but I first needed a good climb to get there.

Except for the escape route to Granby, 13,000 feet was not a comfortable altitude at my location.  The nearest airport to the east was Vance Brand, 30 miles away and there was a lot of high terrain in the way.  Fort Collins was 35 miles away, also with high terrain to clear east of Estes Park.  I had to decide quickly what to do if I didn’t find a climb fast: turn west, which would almost certainly end with a landing in Granby, or turn back east, find lift or risk having to land in a field near Estes Park.

3D view towards Estes Park from above Flattop Mountain. You can see the high terrain east of Estes Park towards Fort Collins. The odds of clearing this terrain in straight glide from my position were fairly low and definitely not something to count on.

I still had a high degree of confidence in the thermal conditions to the east. And, very recently I walked a field at the base of Lumpy Ridge, less than 2 miles north of the town center of Estes Park.  While I was not thrilled about the prospects of potentially having to end my flight there, I felt reasonably confident that I would be able land in that field without damaging the plane (or myself) if I really had to.

2D view of my position above Flattop Mountain. You can see the location of my emergency land-out field just north of the town of Estes Park.

All this went through my mind in the one minute that I flew along the ridge looking for lift.  Lift did not come and I ran out of time.  A decision had to be made: turn left to Granby and land or turn right towards Estes Park and look for a climb?  I turned right.

I still remember vividly the moment when I had to make that decision.  Was it a risky choice?  Subjectively it felt that way.  Objectively, it probably wasn’t.  I was at 13,000 feet.  The field in Estes is at 8,000 feet.  That meant I had about 4,000 feet of altitude to work with before I would have to decide to land.  4,000 feet gave me about 20 minutes to look for lift, maybe more.  I had found strong lift several times that morning already and the conditions in Estes did not look any worse than the ones I had been soaring in for the last hour. And I now had a plan B, i.e I knew where I would land if I had to.

I followed a sun-facing ridge line towards Estes and, fortunately, I only needed a little more than one minute of my 20 minute lift-searching-allowance before I found the climb I was looking for.

It only took 1 minute and 20 seconds from the moment I turned east to finding a climb right above the ridge that runs east from Flattop Mountain. Note the oddly shaped trace during the climb. The lower part shows wind drift from west to east and this changes about half-way through. This is a sign of strong wind-shear and ultimately explained why I would continue to struggle climbing near the Divide.

Eight minutes later I had climbed back to 14,800 feet and the world was once again a better place. But the climb had been odd: between 12,400 and 14,100 the wind drift had been from west to east, and from 14,100 to 14,800 I had to push west to stay in lift and the climb became very uneven.  That also meant the average climb rate was only 3 kt, the worst of the day thus far.

I quickly put that aside, given that I could not be choosey in picking this climb and pushed west again.  Determined not to get so low again, I tried to take the next climb but it was very windblown and difficult to center.  This time, I only managed to average 2 kts but managed to climb to 15,700.

A few miles further west, I once again only found very poor lift, taking me from 15,000 to 15,600 and the climb rate was less than 1.5 kts.  Then, another few miles further west, an even weaker climb topped out at 16,100.  That was the highest I could go.

This 3D trace shows the sequence of weak, uneven and windblown thermals as I tried to gain enough altitude to comfortably push northwest into North Park. The last climb was more of a holding pattern as I tried to make up my mind whether I should continue or abandon the task.

I was clearly high enough to push into North Park and there were clouds on route but I hesitated. And hesitated.  I could get there but would the lift be any better than my last 4 climbs, which were extremely poor and got worse as I moved west?

View into North Park from my position above Trail Ridge Road after my long slog to reach 16k. There seemed to be good clouds all across North Park but would they work better than the weak climbs I had just experienced? If I look at them now in retrospect I can only think, “of course they would have worked!” Clearly my judgment at the time of making the decision was clouded by “recency bias”.

The top of the Divide can be very windy and the thermals there are often weak and uneven.  Maybe, even probably, the conditions would be better if I went on.  But I did not know that.   Would the clouds work?  I wanted to try it and then return if they didn’t work as well as I hoped.  But maybe I wouldn’t even be able to come back?  In which case I would likely be landing in Walden.

On the horizon, exactly in the direction of my first turn point, I could now see a towering cumulonimbus cloud billowing up.  It was only 12:30pm.  That seemed like an early indication of potentially massive overdevelopment in the afternoon. The forecast had not projected any storms but what about this cloud? It certainly looked threatening.  Forecasts have been wrong before.

This is a segment of the same picture as above. But now I had spotted the rose-colored cb at the far side of North Park, above the snow capped peak in the distance that were directly on route. In retrospect, I think my mind was trying to do some mental gymnastics looking for reasons that would provide a justification for not to go on…


Circle by circle I was going back and forth in my mind.  Should I push on or should I return?  I already had my dose of adrenalin earlier when I got low above the ridge.  The probability of completing the task seemed like a coin-toss.  Maybe it would work, maybe not. Another circle of indecision.  Then another. And another.

Circling above Trail Ridge Road below, as I was trying to make up my mind.

I looked towards Granby again where conditions had markedly improved in the last 20 minutes but the bases were still lower than to the east and northwest and the cloud bottoms still weren’t particularly promising.

View towards Grand Lake and Lake Granby from Trail Ridge Road at close to 16k feet. The cloud base was clearly rising but the clouds still didn’t look compelling. (Flattop Mountain, where I was low earlier in the flight, is the level high ground at the left side of the picture above the wing.)

My mind had finally found enough reasons “against” pushing across.  In the next circle, I exited towards the south, having abandoned my task.

After abandoning the task I flew along the west side of Longs Peak before crossing back to the east. The clouds in the distance towards the Flatirons (at the right edge of the picture) still looked very welcoming and that is also where I would find very good climbs again.

I went on and had a good flight on the east side of the Divide, but for the rest of the day I kept second guessing my decision.  I watched the day improve.  Cloud bases rose as one would expect. The weather never overdeveloped except for a few localized virga and showers. In hindsight, I am almost certain that completion of the task would have been possible.  But you have to make these decision in the moment and with information available at the time.

To be clear, the decision to abandon the task was not due to a real or perceived safety risk.  There was no question in my mind that I could reach the airport in Walden or at least another safe landing place.  So the risk I was not willing to take was a sporting risk, not a safety risk.  It was one of potential inconvenience: finding myself sitting on the ground in Walden, having to wait for a retrieve, if things didn’t work out.

The real question is of course: what will I do next time when completion seems uncertain?  How confident do I have to be in my ability to complete my task?  I must be honest: there will never be 100% certainty.  Does it make sense to push on if the chance of completing the task is only 25%?  Probably not.  If the chance is 75%?  Probably.  If it is 50%?  I still don’t know.

My flight track is here.

Lessons Learned

  • 13k MSL Can Be Really Low.  It always depends on where you are relative to safe landing places and any terrain in between.  13k above the Divide west of Estes Park is too low for comfort.  I should not let this happen again.
  • Walking Fields Pays Off.  Having walked the field at the bottom of Lumpy Ridge, I knew where to find it and how to fly an approach if I needed to.  This gave me the confidence to look for lift where I was almost sure to find it, and the clarity of thought to look for it without stressing out over whether or not I would be able to glide out to the prairie.  Had I not known this field, diverting to Granby would have been my only viable choice.
  • Don’t Ever Get Into a Marginal Situation without a Pre-Decided Plan B.  When I approached the Divide I was so confident that I would find lift on top that I had not pre-decided what I would do if I that did not materialize.  So I only had one minute to consider my options.  This felt too short and too stressful.  It’s best to make a Plan B while you still have a lot of options so you just have to execute what you already decided. (This is no different to the decision of what to do in case of a rope break or any other emergency situation.  Don’t wait to decide what to do when it happens.  You must know what to do in advance.)
  • Don’t let your most recent experience in a small area cloud your judgement (recency bias).  The day started very strong with solid, reliable climbs along the foothills.  When the small area immediately next to the Divide did not work well, I lost confidence in the conditions across the divide as well.  Similarly, I did not anticipate that the Divide would not work because I had found such great lift over the foothills.  I must try to avoid falling victim of recency bias.
  • Learn to better differentiate between safety risks and sporting risks.  These are very different things.  Never take safety risks.
  • Pre-declare (to yourself) the level of sporting risk you are willing to take.  Landing back at home is never 100% certain on a XC flight.  It may be useful to pre-declare before the flight the land-out probability you are willing to take.  E.g., “Today I am willing to accept a 30% land-out probability.”  Then you can reflect during the flight what you believe the odds of landing out are if you continue on task. It might make it easier to decide whether to go on.
  • Pre-arrange a retrieve in case you need it.  There is huge peace of mind knowing that someone will come and get you if you have to land away from the home field. In fact, unless this is pre-arranged it’s really difficult to accept a significant land-out risk.

Into Wyoming: 4th Diamond Distance Attempt

You see, flying takes three things: Hard work, perseverance and… hard work.

You said “hard work” twice.

That’s because it takes twice as much work as perseverance.

(from the movie “Chicken Run” by Aardman Animations)

Yesterday the Soaring Society of Boulder held its annual “Workfest” – a club event to clean and wax the club ships and get all other equipment in top shape.  It was also the best soaring day of the week and one of the last remaining OLC Speed League weekends, so the plan was to start work as early as 7am so we could finish early and fly as soon as the bulk of the work would be finished.

My alarm was set for 5:15 am and by 6:30 I was among the first to arrive at the field.  I figured it might be one of the last chances of the year to attempt a Diamond Distance Task (a pre-declared 500km flight with no more than 3 turn points).  I wanted to get the work going as soon as possible so we could get in the air.  In addition, I wanted to secure an early slot on the tow list – essential to have enough time to complete my soaring task.

I had planned my task based on the following considerations: higher cloud bases to the north (17+k) than to the south (~15k).  Stay east of the divide due to multiple areas of expected OD in the afternoon in the west that might make a return over the mountains impossible.  Light winds, including in the Laramie valley (which is usually quite windy). Strong late afternoon conditions over the prairie up to Ft. Collins. The task was:

Start: Bighorn Mountain (14km west of Boulder).  TP1: Roger Canyon (ne of Laramie). TP2: Bergen Peak (sw of Golden). TP3: Horsetooth Reservoir. Finish: Rocky Flats. Task Distance: 311.2 miles = 500.8 km.

By 12:30 pm we were more or less done with the essential chores and I was ready to go.  While the valley was still inverted, the tow distance was fortunately more reasonable than on July 19, and I was able to release in the first good lift above Nugget Ridge. After a short climb I rounded my start point above Bighorn Mountain (just inside the OLC start cylinder), returned to Nugget Ridge and stair-stepped my way back west toward the clouds with short successive climbs above Gold Lake, Ward, and the Brainard Lake Winter Parking Lot. From there I headed towards a nice looking cloud 10 miles north, fed by the NE ridge of Mount Meeker, which took me to cloud base.

Circling above the north-east ridge of Mount Meeker, where I connected with the clouds.

(Note for those new to flying from Boulder: stair-stepping (i.e. taking several short climbs above one of the ridges with pushes to the west in-between) is a frequently required technique to get into better lift close to the Continental Divide, where the depth and strength of the thermals is usually much greater than over the lower foothills.)

Soaring always feels best when you’re connected to the clouds, and when a whole row of good looking clouds marks a viable path forward.  To quote Bob Caldwell, “the fastest way from point A to point B is rarely a straight line”.  In my case, the best line ahead seemed to be a westerly route through Rocky Mountains National Park, crossing the Mummy Range near Ypsilon Mountain and from there directly north via Kinikinik towards the Laramie Basin.

The northern part of Rocky Mountains National Park, between Mummy Range and the Never Summer Mountains is a tricky area where you definitely do not want to get low.  The only ways out from there are to the south via La Poudre Pass ( 10,200 ft) towards some fields near Grand Lake or to the west via Cameron Pass (10,300 ft) towards a landout field near Gould.  The airports and fields on the eastern side of the foothills are 30 miles away and probably not reachable once you’re low.  I only feel comfortable flying in this area when I have enough altitude to be able to glide over the mountain ridge to the west into North Park.  Hence, I was careful not to drop below 15,000 feet. You can take a closer look at this area by examining my Boulder 250 Soaring Map.

Be particularly cautious when flying over the area circled in red between the Never Summer Mountains in the west and the Mummy Range in the east. There are no places to land in this area and it may be impossible to get out if you get low.

Fortunately, all the clouds worked without fail and I was making good progress heading north.  As I crossed into Wyoming I was able to connect with a convergence line marked by a massive step in the height of the cloud bases (about 3,000-4,000 feet difference).  I followed the line on the higher west side, which took me across US 287 and I-80 towards the higher ground east of Laramie.

There I had to leave the convergence and head north into a blue area with another 13 miles to go to reach my turnpoint at Roger Canyon.  Two small emerging clouds gave me some extra boost and then I jumped into the blue.

A blue hole as I headed north towards my first turn point. The town of Laramie is to the left of the plane (not visible in the picture)

Laramie airport was to my left and in easy glide range.  I closely watched the sky as I headed north and saw a new cloud appearing to the southwest of my turnpoint.  I dashed for my turnpoint, rounded it at 1:50pm, and headed straight to the newly formed cloud.  It wasn’t as good as I had expected it to be but in combination with the next climb it got me back to cloud base.

As I circled I had time to plan my southbound route.  The convergence line had moved further west under a sky that already showed early signs of overdevelopment.  Following it would represent a detour that would once again lead me across the same high and unlandable terrain that I had crossed earlier.  The alternative was a more direct route below the lower clouds further east but it looked less convincing.  If in doubt I have no problem to opt for the higher, if longer, westerly route.  I just had to be careful to keep landable places in easy reach at all times.

On my southbound return as I’m crossing I-80 southeast of Laramie. You can see the convergence line ahead with lower cloud bases on the left and higher cloud bases straight ahead in front of the nose. The snow capped peaks in the distance are the Never Summer Mountains. The direct route to TP2 would have been below the clouds 15 degrees to the left of the nose. I opted to go straight under the higher cloud bases, and over the higher terrain .

It proved to be the right choice. The convergence worked even better than before and all the darkening clouds provided good lift even as light snow-virga started to fall. I made great time and was getting more and more optimistic that I would be able to complete my task despite the relatively late start.

A noteworthy moment came as I approached the Mummy Range from the north.  My last climb had been mediocre and I had abandoned it in favor of a great looking cloud above Comanche Peak.  I was getting a bit low, approaching 14,000 feet and a lot depended on the cloud working.  If it didn’t I would not be able to maintain my southerly route but would instead have to divert eastwards along the ridge towards Loveland.  Scraping over the Mummy Ridge and flying straight into the Estes Park basin at considerably less that 14,000 feet would not be a good idea…  I had a clear escape path towards Loveland but going there would considerably hurt my progress.

I tugged under the cloud above Comanche Peak and to my great relief hooked a solid 7 kt climb, one of my strongest ascents of the day, taking me right back to cloud base at 16,000 feet. I distinctly remember saying out loud, “Wow, today is really good!” My confidence of completing the task had just received another huge boost.

Minutes later I crossed the Mummy Ridge into the Estes Park basin.  And what I saw was astonishing:  the sky ahead had turned completely blue.  I had flown under such dark skies for the last 45 minutes that this came totally unexpected. A small lonesome cloud sat above the Twin Sisters but even it disappeared as I headed towards it.

A quote from Daniel Sazhin, a current US representative at the Junior World’s Championships came to my mind, “Soaring is a manic depressive sport.” One minute you feel great, like it’s the best day ever, then, one minute later, you are down in the dumps.

Well, to be honest, I wasn’t quite down in the dumps, at least not yet.  I was still at more than 14,000 feet, I had past Estes Park, and Boulder was already well within glide range.  But my hope to complete the task was eroding quickly.  I got on the radio and asked other pilots nearby how they were fairing and quickly got confirmation that the conditions east of the divide had become very soft.

There were still good-looking cloud streets on the west side of the Divide.  But following them would take me away from my next turn point, not towards it.  I briefly considered abandoning my task and just following the lift lines but then I thought, “if I want to learn something new, I just have to stick with my task and see how far I can get.”

As soon as I made that decision, new hope started to form in my head.  All of the foothills were now in the sun.  Surely, the blue sky was just the consequence of a down-cycle, perhaps overdevelopment had preceded it while I was in the north.  Now that the sun was heating  the ground again, it was just a matter of time for new thermals to form and new clouds to appear.

I convinced myself that this is what would happen and my task now was to play for time while trying to continue to inch southwards.  As I continued on course, I dialed my speed down to minimum sink and tried to just float along.  There was some wind from the south east, maybe I could stay up in ridge lift?  I tried the south eastern flank of Mount Meeker where I had found good lift in the morning but now there was no thermal to be found and the ridge definitely did not work either.

I looked for other terrain features that might work considering the angle of the sun and the direction of the wind.  Meadow Mountain, south of Allenspark, looked promising, but again, nothing.  I dropped below 12,000 feet.  I had to find something soon otherwise I would have to head back out towards Boulder and I was concerned that the further east I would get, the more challenging it would be to climb back out.

Then some wisps appeared to be coming off a hill south-east of Meadow Mountain.  To my surprise the wind had picked up to 16 kts and the rising bubbles provided very narrow and uneven lift.  Slowly I gained more than 2,000 feet.  Deep in the foothills it makes a huge difference whether you’re at 12,000 or at 14,000 ft.

The only remaining clouds looked to be just west of the Divide.  If I could get there, maybe I could climb back to cloud base.  I had just enough altitude to fly over Mt. Audubon and follow the Continental Divide south from there.  Weak and completely wind-blown thermals were coming off Niwot Ridge and the Arapaho Ridge.  I was surprised that I could not find any ridge lift right above the steep east-facing cliffs along the divide even though the wind was blowing directly towards the ridge line.

In the meantime the clouds had moved further west and there was no reason to hang out at the Divide which didn’t work anyway.  With that I continued to inch towards my 2nd turn point looking for lift in the blue above any promising terrain feature.   Weak climbs near Eldora and Rollinsville topped out at 12,000 feet, just enough to stay on course and keep Boulder in glide range.

Northwest of Blackhawk I was down to 11,500 ft.  I had just enough altitude to approach the top of a hill, vouching to fly out towards Eldora Canyon (and Boulder) if I could not find any climb.  Once again, I found lift at the last minute and managed to rise back up to 14,800 ft, the highest I had been in 1 1/2 hours!

This was the climb I needed to round Bergen Peak, my second turnpoint.   I made Bergen at 13,100 ft.  It was 5:45 pm and there was still no cloud in the sky.  It was clear that the day would soon be coming to an end.  I had little hope left in being able to complete my task but I still I felt compelled to see how far I could get.  Maybe I would be surprised by a “glass off” evening effect over the prairie that would propel me forward?

On the other hand, it still seemed a bit too early to head out over the plains, and I had just enough altitude that I would be able to reach and fly along the top of Thorodin Mountain.  That was my best hope for another climb to a higher altitude.  At the north end of Thorodin I did indeed find some lift.  However, instead of the boost I had secretly hoped for, it topped out at 12,500 ft.

I continued past the Flatirons to Bighorn Mountain to close whatever small triangle there was to score and kept going past Bald Mountain (nothing) towards Lyons.  Just as I considered returning to Boulder I found another climb over the hogback.  This one was different from the ones before.  The air was smooth and the thermal was wide and even.  For a moment I found one last glimmer of hope against my better judgement.   In 3kt lift I climbed in perfect circles to … 10,800 ft.

At the same time high clouds moved in putting everything to the north into complete overcast.  I knew then that the day was finally over.  Although I kept going further north to see how far I could get, I put Boulder into my flight computer to ensure that I would stay within glide.

As expected, I didn’t get very far… Half way to Carter Reservoir and still 18 miles shy of my final turn point I finally had to face the fact that completion of my task wasn’t to be.  When I reached a projected arrival altitude of 1,500 AGL at Boulder at MC3 I made a 180 degree turn towards the airport where I landed in glassy smooth conditions at 7:36 pm.

I flew 445 km in 5 3/4 hours.  The first 2 1/2 hours were reasonably fast.  The rest was very slow.  My flight track is here.

Lessons Learned

  • Don’t give up, even if it looks hard.  After the sudden deterioration of the soaring conditions on course, it seemed almost inconceivable that I would make it to the second turn point. And several times I found a climb – just before I had to change course – allowing me to continue.  Bit by bit I made it to TP2.  I only quit when there was no question in my mind that continuing would result in landing out.
  • Expect the unexpected and hang on. -The conditions can literally change from one minute to the next. I just came out of my fastest stretch and my strongest climb of the day when suddenly the route ahead was almost dead.  If conditions can turn off quickly, they can also turn on quickly.  So hang in there if you can.
  • Gear-shifting is really a thing.  I read a lot about this but it was never so apparent to me than today that you may have to shift from one minute to the next to adapt your flying style to the conditions ahead.
  • Always know your escape paths.  I was glad that I had done my homework when crossing the unlandable high terrain between the Mummy Range and the Never Summer Mountains. I knew how high I had to be and I knew where to go if things went sour unexpectedly.
  • Decisions can provide hope and focus your mind.  This is more a psychological point than anything else.  I already learned that waffling is not a good thing because it can make you do pointless things. But today I experienced the positive effects when I firmly stuck to my objective.
  • Sometimes the thermals cycle – and sometimes they don’t.  Several times I have seen very rapid up and down cycles of thermal conditions.  Today they just cycled down and did not come back.  That can happen, too.
  • A long marginal flight is hard work and the necessary concentration is exhausting.  I was pretty spent after getting up at 5:15 am, working on ship maintenance all morning, and then flying for six hours with the last 3 1/2 hours in marginal conditions, requiring my full attention.

In addition to these lessons, I have also collected a few questions to which I have found no solid answer. If anyone can contribute to my understanding, please let me know.

Unanswered Questions

  • Why was there no ridge lift?  My flight computer showed 15-18 kts of easterly winds (sometimes straight from the east, sometimes from the south-east) as I was flying at about 13,500 feet above the steep east-facing ridge of the Continental Divide that was just a few hundred feet lower.  The direction of the wind is also confirmed by the wind drift when I tried to thermal in that area.  Why was the ridge not working?  Is it possible that the wind only blew at my altitude but not (or much weaker) lower to the ground?  I have not been able to figure this out although I have speculated about it below.
  • When can I expect the “glass-off” phenomenon at the end of the day?  And when not? Several times I have experienced the amazing phenomenon of the entire prairie lifting at the end of a soaring day.  Yesterday this did not happen.  I suspect this had to do with the winds.  On days when it happens, the wind over the foothills tends to shift westerly in the evenings as a result of cooling over the hills as the sun angle there becomes very flat.  The cooling air streams down towards the prairie, meeting the air over the plains and causing a weak but wide-spread convergence that lifts the air over the plains.  Yesterday, the wind remained easterly all across the foothills (e.g. see my last climb near Lyons), i.e. there was no convergence over the plains.  Which would explain why this phenomenon did not occur.  I might just have answered my question.  But is this right?
  • What caused the sudden collapse of the thermals in the afternoon?  And why was there suddenly so much wind from the east?  Are these two observations related? Why did the thermals not come back with all the afternoon sunshine?  The only possible explanation I could come up with is the inflow of warm air from the east at a level of about 13k feet.  This would explain the easterly wind at that altitude, it would explain why the thermals above the ridges near the divide were so wind-blown and turbulent, why they topped out at 13k feet, and it would even explain why there was no workable lift at ridge top level along the divide (because there was no or not much wind below moving up the slope – the wind may have just been at ridge top level, blowing across the ridge but not blowing up along the slope…  All this seems a bit speculative.  Anyway, does this seem true and does anyone know if this is an exceptional phenomenon or if it happens more often?  (I had not experienced it before.)