Wednesday, July 23, 2008

17,990 feet Over Boulder: Serious hypoxia and?

A few weeks ago I had the good fortune to enjoy some truly epic flying conditions off of Lookout Mountain, near Golden, Colorado. Those conditions took me to 14,500 feet. I've flown off of Lookout hundreds of times, but only reached that altitude maybe a half-dozen times. Today I flew at over 16,000 feet for far too long, and hit the FAA ceiling of 18,000 feet. This was an interesting experience, one of the top three "weird" things I've ever had happen on a paraglider. Here's the story, pounded out fast about July 15th but forgot to post it up.

The morning started out with a nice hike up Green Mountain. Despite a meniscus tear I can still hike on trails, I just can't walk around Home Depot on the cement floors for more than 15 minutes without starting to hobble like, well, a guy with a torn meniscus. At 10:00 in the morning the temperature was already hot, and the morning thermal cycles were strong enough to move the trees around on top of Green. All other plans were canceled, time to go fly.

By about 1:00 I was on launch in Golden with MR and a few other pilots. It was great to see MR and Rusty were still at it! But conditions seemed rather weak, with a few pilots sinking out. For whatever reason the day just wasn't on there yet. Eventually MR and I launched, and climbed out slowly out to about 9500 feet (my vario is in meters so feet are an approximation). The rest of the pilots soon joined in, and we bounced of the inversion for a while. There was a guy on a yellow Advance already heading north, but the Boom 5 with bar made catching up pretty simple. I passed under him and headed on before hitting a 5m/s thermal, which was about double what we had gotten so far. BOOM! Soon I was climbing through 15,000 feet, a new record for flying over the Front Range for me, and I decided to start gliding north as 15,000 feet is, ah, plenty high. Yeah!

That's when the first jet went by overhead. Not super close, but close enough to have a good look. My heart rate went up a little, but the sky is big. It's not uncommon to have jets fly overheard, that one was just a little bit closer than I like. I'd like to know what the guy on the yellow Advance got up to--the last time I saw him he was many thousands of feet below me and still heading north. (Edit--you can read Sam's account and see his excellent photos here, what a day! Glad Sam took some photos 'cause I didn't.)

Denver International Airport is about 30 miles east of Lookout, and it's normal for the jets heading west to overfly us as we head north to Boulder. No big deal, I continued gliding north. Strangely, I was still climbing despite having some bar on and flying straight. 16,000 feet is when I started to get pretty excited and notice the symptoms of hypoxia (slow thinking, less than prompt reactions, the usual). But a perfect cloud street was popping in front of me toward Boulder, and I wanted to be out of the area where the jets were so I stayed on bar, and kept slowly climbing.

At about 16,500 I hit the west winds and started to drift east a bit, but made sure to crab so that I was nowhere near DIA airspace (I stayed west of the Boulder-Golden road to be sure). 17,000 feet is when I pulled big ears, and the second and third jets went by. Again, not close enough to file an incident report, but a jet looks pretty big when you're a butterfly. My heart rate accelerated dramatically.
By this time I was high enough to have a clear visual on DIA, and I kept a very sharp eye to the east. I didn't want to fly back through the lift I'd just been in as that would have put me above 18,000 for sure (base looked to be about 20,000), and the clouds to my west looked even harder. Clouds with flat hard bases mean stronger lift, something I did not need. I couldn't really go east as that would put me more toward DIA. I pondered spiral diving, but would that put me back into the altitude range of the jets coming out of DIA?

So I kept heading north. By now I was well north of DIA and right at the FAA ceiling for hang and paragliders, 18,000 feet. I let myself drift a bit farther east, still cautious of the Denver airspace, and flew east of Boulder. There's a very active drop zone in Boulder, I didn't want any part of that. Then another jet flew right under me, and my heart rate really went ballistic. I also noticed that I couldn't relax my hands anymore, my lips were tingling and my thinking process very, very slow. I was also frozen--I'd launched expecting to maybe hit 10,000, now I was near 18,000 and cold.

There was a perfect line of clouds heading east, but I was feeling pretty concerned about the air traffic, was noticeably hypoxic and had generally had enough. I flew north toward a big blue hole, which normally means sinking air. At this point my hands and forearms were cramped clubs. I was not losing altitude, clouds kept popping above me... Normally when you get beamed to 17,000 feet plus you fly out of the lift and plummet back to a much more reasonable altitude where it's possible to recover from the oxygen deprivation. I'd now been above 15,000 feet for close to an hour, and decided that I would just glide until I was below 9,000. The ground out north of Longmont is probably at about 5,000, so if I felt like continuing I could from that altitude. But I still wasn't losing altitude. I'd been watching the sky carefully for signs of serious over development (or jets) and there just weren't any so I wasn't concerned about that, but my body was in full revolt. I was as near puking as I've ever been in the air, and had all the fun symptoms of both normal old paragliding hypoxia and also the ever-fun altitude sickness more familiar from climbing too high too fast on mountains. As hypoxic as I was, I didn't want to start spiral diving to lose altitude and add more stress to my body, but with non-functional hands and a seriously messed up mind the situation was not what I like when flying. If I continued to gain altitude I would be in controlled airspace. But that might be the least of the immediate problems--what if this got so bad that I blacked out? I've been to near 20,000 feet+ over Telluride and about 18,000 feet a lot in Aspen, but I was well-acclimated at the time. At a site where 11,000 feet is considered high I'd just flown high enough for long enough to encounter a new physiological wall, something I'd never experienced anywhere else in flying.

I mulled the options in my mind while sucking huge lung fulls of air in. I know from being high in the mountains that even while at relative rest my pulse and respiration often at least doubles, but this was much, much more intense. I wasn't panicked, but I was sure as hell stressed out. Jets, altitude, something was really going wrong...

I literally could not open my hands, and my glider inputs were reduced to moving my arms with my biceps and lats. I fly like that a lot when cold, but I just wasn't that cold... As my vision narrowed I decided I was extremely hypoxic and near systems shut down. I contemplated throwing my reserve, but throwing my reserve at just under 18,000 feet didn't seem like a good idea. I figured that if I were to pass out I would likely wake up before I hit the ground as I was at least two miles above it, plus I wasn't sure if I could make my hands work well enough to throw the reserve anyhow. Like I said, new physiological and mental ground... I focused intensely on staying with the program and continuing to breathe as more and more of my body cramped up. I have never had anything like this happen in flying, it was kinda traumatic.

Eventually the sink alarm went off, and feeling started to return to my arms and face as I continued to glide northeast. By the time I was down to 10,000 feet I felt pretty good, but went through the most excruciating "screaming barfies" I've had in years as I windmilled my arms to pump blood back through them. I don't think the barfies were just from the cold as I was reasonably warm, it was the cramps that kept my blood from circulating. I flew straight through some decent lift while sorting my hands out, I just didn't want to take it high again.

By 8,000 feet I realized I'd flown myself into a large shaded area, and there was likely no getting back up. This really didn't both me too much. The west winds had pushed me well north and east toward Greeley, not sure where exactly as I didn't bother to put a waypoint into my GPS for launch. Eventually the west winds turned to east winds and I landed smoothly next to a gigantic green lawn perfect for folding my glider up on. The lawn's owner came up, real friendly guy, and we talked as I folded. I still had my balaclava on, which must have seemed a bit odd in the heat (102 according to my host), but he rolled with it. A liter of water and some food put the situation more or less right, but in retrospect I find it somewhere between humorous and frightening that I forgot to ask Mr. Lawn where I was--and that I didn’t think to take my balaclava off... My mind still wasn't all there. I knew I had to go east and south to get my truck back at launch, and my host told me it was about 50 or 60 miles away as the crow flies. Not an epic flight in terms of distance, but epic in lots of other ways.

The hitchhiking went pretty well; a solid guy named Jim picked me up and drove me into Longmont, where we did a friendly cash deal that found me back at my truck in reasonably short order. As always, I enjoyed the ride and talking to a random guy about life, politics and whatever else was going on. If Jim finds this scribble, thanks for the ride, absolutely worth it in many ways, hope to hear from you in the future!

Tonight I started to research the effects of hypoxia to try and understand my experience. Hypoxia/altitude sickness certainly explains the muddled mind, urge to vomit and so on, but cramped hands and tingling are not the usual course of the experience, at least according to the ten minutes I spent on the web tonight. Those symptoms fit much better with hyperventilation, where the calcium levels in your body can get seriously whacked. I had consciously been breathing deeply and smoothly while high, I've found that really helps me with altitude while climbing. Had I done too much of it? Had the stress from the jets sent me over the edge? Does hyperventilation cause cramps and tingling faster at high altitude de to some combination of lower partial pressures and oxygen saturation? Who knows, I'll do some more research and find somebody who does, 'cause that was an experience I don't want to repeat. Lookout mountain sure delivered the goods...

July 23rd note: I'm more certain now that, while I was certainly hypoxic, the situation was likely compounded through hyperventilation-induced problems.

I've also checked a sectional for the airspace rules around DIA, I was not in controlled airspace at any point. It's just that neither were the jets, and they move a lot faster than I do. I would suggest staying below 15,000 feet anywhere along the Front Range, I did not enjoy the experience of so much air traffic even if it was relatively far away. It's not something to gamble with in my opinion.

6 comments:

Bill said...

Will,
Puking, what fun! Like teenagers and beer.

You saw a lot of air traffic cause there are three federal airways on the route you flew. V356, which goes over the big bend in the railroad tracks just south of 72, V 85 that goes right through Lyons and V 575 that goes between Berthod and Love land. I have flown on a jet on V 356 and was over 18 thousand at the time. Still good to keep an extra eye out on those spots.

You're old instructor Billbill@flyawayparagliding.com

Mark said...

What!? You didn't take pictures! ;)

Will Gadd said...

Make sure you check out Sam's story and pictures from the day, link above, epic!

Bill, good to hear from you! Yeah, the class E Federal Airways really haven't been an issue when flying at Golden before as it is extremely rare we reach altitudes that departing jets will also be flying at. The sky is big, but for me the experience was not positive, and not one I'd care to repeat. Might be worth sharing the information on the airways a bit with the club (I'm sure everyone knows about 'em to some extent, but perhaps not how many planes there are in 'em!)...

Mark, check the link to Sam's post, wicked photos.

webby said...

good story will, glad you got through it. Check out http://usa2008-paragliding.blogspot.com/2008/07/01708-chelan-classic-fly-day-3.html for an dumb flight from me

Brad Sander said...
This comment has been removed by the author.
Brad Sander said...

Will,
Just stumbled on your blog and 2 reactions, damn I was in Denver at the same time and forgot Josh said your were going to be around! Second is thanks for sharing your experience with hypoxia it's a good reminder. Effects of altitude are not predictable and just because we have been fine at a certain altitude in the past doesn't mean our bodies will react the same next time.

Sorry I missed you, do you have an idea where we can meet up in the future? because I do!

That was a great story thanks for sharing it,
Brad