Hypothermia

[Darin Banner]

Companion forum thread to: Hypothermia

What is hypothermia, and how do you treat it with an ultralight backcountry gear kit?

[Ryan Jordan]

Big thanks to Darin for updating our Hypothermia article, which has been here for years! This condition remains the most common emergency scenario we experience. It’s so good to have a refresher and have hypothermia management skills in your back pocket.

[Terran Terran]

Hyperthermia seems to be of recent concern.

Reports of a death on the CT. Unknown causes. Lots of sun lately and it can be pretty intense at high altitude.

Other deaths in Nevada. I used to hike the C2C folks would turn around in the heat and pass out. They start out when it’s cool, then they get stuck in it.
Be careful out there.

[DWR D]

Brings to mind the several times I have read advice that you don’t need to take a rain jacket on certain hikes in certain areas because, ‘it never rains there’… advice given by someone who had only hiked there once. All in the name of going ultra light. Me, I always take at least a light rain top… and a little extra warmth layer than the anticipated need… consequences of being wrong about the weather can be catastrophic.

[Ted C]

Excellent article. This is one of the most concise and easily understood discussions of the physiology of hypothermia I’ve ever read! Thank you for sharing your story and providing such a sound understanding of this insidious killer.

There isn’t the slightest doubt in my mind that you saved that boy’s life. He didn’t know what was happening to him, nor did he have the physical ability to do anything about it. He was totally dependent on someone else to save his life.

Note to self: Read this article at least once every year for the rest of my hiking life!

If I may, I’d like to add my experience from several decades ago with this insidious killer . It was a beautiful fall day. No rain, just crisp cool air, probably in the low 40’s and a mild breeze. The trail I was taking was steep and difficult to follow. Consequently, I pushed a little harder so as not to be late meeting my friend who was coming in on a different trail. Result, I sweat more than normal, and didn’t stop to eat or drink. I was getting tired but pushed on in order to not be late getting to our rendezvous location. I didn’t know it, but I was already in the early stags of hypothermia. When I got to the ridge, fortunately, I tripped and fell. That’s when I realized I was in trouble. It took a lot of effort to get my wet shirt off and put on my jacket. Getting the zipper started was out of the question. I managed to eat some food and drink some water. Then I rested for a while. Had I not tripped, I probably would have pushed on toward our meeting place, where I most likely would have died. Unknown to me at the time, my hiking partner injured his leg near his trailhead and was probably in the hospital before I got to the ridge.

Whenever I think to myself, I can push through to____ , I stop right there, sit down and ask myself, as you pointed out, am I wet, tired, thirsty, hungry, hurting or cold. If I answer yes to any of these, I deal with it then and there. Then, maybe, I’ll continue as long as none of these reoccur. As a solo hiker, prevention is the only thing I can do. If I become hypothermic, like the tough-guy in your story, I’m just a deadman walking.

Thanks again for your excellent reminder of what’s lurking in our decisions.

[AK Granola]

I experienced the first stage of hypothermia years ago on a fishing boat. It was spitting rain and windy after several hours of fishing for halibut, and I had started shivering violently. I couldn’t speak properly, and despite a wool sweater (no shell) I just got colder and colder. I finally relaxed and stopped shivering, and just felt sleepy at that point and didn’t care any more. At that point friends realized I was not right in the head, and covered me in layers and got me out of the wind down near the head. Shortly after that we arrived in port and they helped me out of the boat and into a hot shower. I didn’t realize until much later the danger I could have been in. Now when I hike alone, I am careful to stay warm always. I stop to put layers on as soon as I feel the need and don’t wait until I’m seriously cold. And in cold rainy weather is not the time to cut calories! I also ignore people who say not to bring rain layers – anywhere! They are always in my pack.

[Ian H]

Good article, thanks Darin. A useful rule of thumb is if your hands and feet are warm you’re not hypothermic, because the body shuts off the peripheral circulation first to save core heat. If they feel cold, time to stop and do a risk assessment – are they just wet, or are you starting to get hypothermia?

One question – you mention the “ten essentials” in a day pack, what are they? Like a trail run mandatory gear list, or something else? I’d always have a rain jacket and pants, even on a dry summer’s day, and a bivvy bag or tarp in winter/wet weather – something to keep you alive till the helicopter comes to the PLB signal. I also have a low threshold for carrying a light sleeping bag like a Marmot Phase 30 (500gm) in worse weather. At the Mayo Clinic (Rochester MN) in the 1980s, before cellphones were much use, on-call staff were advised to carry a down sleeping bag in their car, because they lost a couple of staff a year from sliding off icy roads at night, and dying before anyone came by.

[Arthur]

I was a resident (we were called Fellows)  for at Mayo in Rochester in the 80’s.  I never heard of any staff dying in this manor.  There was one skiing by himself who broke his femur and died.  I also never heard of any guidance for sleeping bags in cars. Urban myth or were you there after me?

[Ian H]

Arthur, that would have been 89. Not sure whether it was a ‘drop bear’ story about car freezing to scare foreigners applying for a job, but the locals did mention they’d had a week of -50 that winter. It may have been an urban myth or a single incident, but it scared the proverbial out of me, especially as the pay was lousy so I’d have a cheap car. I was going for an orthopaedic fellow job where callbacks were common, and the rule was you had to wear a business suit and tie (even at 3am!) when coming in – a nicely ironed cotton shirt is not appropriate clothing for hypothermia!

I didn’t take the job for mainly family reasons, and I got a better offer back home in Sydney. I always carry some scrubs and surgical drapes (plastic/paper waterproof) in the car, mainly because I once ruined a good pair of suit pants changing a wheel on the way to work. But they would improvise as a bivvy bag :)

The other hypothermia preventer is a pee bottle. Obviously it saves you getting out of a nice warm sleeping bag and standing in the rain. But it also means you can drink at bedtime, and stay well-hydrated.

[MJ H]

Obviously it saves you getting out of a nice warm sleeping bag and standing in the rain. But it also means you can drink at bedtime, and stay well-hydrated.

It took me a second before I understood this correctly.

[Arthur]

Ian, after my time.  If I was offered a Sydney position, I would have taken it too.

[Darin Banner]

Hi Ian! Sorry for the late response. I’m just seeing your question. The Mountaineers defined the “ten essentials” in their book Freedom of the Hills in  1974. In more recent editions, they’ve moved from a list of 10 items to 10 systems (e.g. navigation, insulation, shelter). That’s the approach I take and teach. It gives a foundation you can adjust to meet the needs of your outing. This is a good overview: https://en.m.wikipedia.org/wiki/Ten_Essentials

[David Thomas]

The sleeping bag (and food, water, tools, warm clothes, boots, light, etc) in your car trunk is Alaska Winter Driving 101.  Both our college students who went to Minnesota would do the same there.  Sure, -40F in MN isn’t as removed as on a remote Alaskan Highway, but could be just as deadly if snow drifts shut the roads down or if your car slides into a ditch.

With those items, it just becomes winter camping in the most bomber tent you’ve ever had.

Even more important is to never leave to go over the pass without topping off the fuel tank.  Then you have several days of heat, tunes, and device charging.

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