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Reader Poll: Preventing Frozen Boots in Winter

Scarpa Plastic Mountaineering Boots

Q: How do you prevent your boots or shoe system from freezing at night on overnight winter backpacking and mountaineering trips?

Group Safety in Winter

I'm planning on leading a few winter backpacking trips this winter in New Hampshire that require full winter gear and I want to know what kind of boot system you'd want other people in your party to use on trips averaging 8-10 miles per day with 3,000 feet of elevation gain, daytime temperatures in the single digits (F) and night time temperatures between -10 to -20 below zero (F).

My goal is to introduce experienced winter hikers to the joys and techniques of winter camping. If you've ever done a multi-day trip like this, it's a ton of fun and the views can be fantastic. But winter camping requires some new skills and has its own set of special hazards that you don't encounter in day-only outings.

Preventing Frozen Boots

Given that most peoples' feet and calves sweat in winter, I see three approaches to preventing frozen boots in winter:

  1. Wear mountaineering boots with removable liners that you can sleep with in your sleeping bag at night. This lets them dry out and prevents them from freezing in subzero temperatures. If done for a limited time over one or two nights, it's unlikely that the moisture in the liners will significantly degrade the warmth of your down sleeping bag.
  2. Wear a vapor barrier liner in your boots to prevent them from absorbing perspiration. This is pretty hardcore and a lot of people find vapor barriers to be uncomfortable, but it is an option. In fact, many people do it with number #1 above, in extreme conditions to boost the warmth of their boots.
  3. If your boots don't have removable liners, sleep with them in your sleeping bag. It's the only way you can dry them out and keep them from freezing.

I don't see many other options that don't compromise group safety, but I want to make sure I'm not being overly cautious in the gear requirements that I post for these trips.

If you can share your own experience on this issue, I'd appreciate the input.

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26 comments

  1. Option two is unlikely to help. The boots will freeze regardless of whether they are wet or not. Plus, they're more likely to get wet just from being used in the snow.

    Double boots, with the liners kept in your bag, is really the only way to have thawed boots in the morning. On some trips that I've led, we've collected boots in the morning and warmed them by a fire in order to provide extra service to the clients.

    in reality, we often put on frozen boots in the morning. This isn't necessarily a huge problem. But if people have cold feet, frozen boots and the morning activities are inactive, it can be an issue. I often resort to doing foot checks where I actually look and touch participants bare feet to make sure no one is developing problems.

    Most Baffin brand boots have removable liners. They're cheaper and less rigid than mountaineering boots.

  2. Extra long sleeping bag. Make sure clients bring plastic grocery bag to wrap boots, then stick at foot of bag. Can also do chem heat pads in boots, then stuff tops w dry socks. Won't dry (in either case) but will keep from freezing.

    BTW I think I was behind you a couple weeks ago on wonalancet loop. Saw your blog photo of ledge w ice, recent dusting of snow. If you were the ones who skirted the ledge, thanks–I followed your trail.

  3. @Maineguide – yep that was us.

    I also buy extra long sleeping bags and bivies for winter. Easier to sleep with your gear in.

  4. Jack – thanks for the reminder about Baffin. I couldn't remember which pack boots had removable liners.

  5. Have to disagree with Jack on his first point, I'm afraid. Tramping through slush is one thing, but at the temperatures you're talking about, the outsides of your boots really aren't going to get significantly damp – any moisture is coming from the inside of the boot. I'm a VBL guy all the way as you know. Having said that, we all plow our own furrow…

    I'd say #3 is the worst option. I think you just end up with a wet bag and wet boots.

  6. Bringing cold gear into a sleeping bag with you will chill your core temp down and I recommend against it.

    In winter I wear a trail-runner style ankle-high "boot" with a Gore-Tex liner. At night I put them under my head (outside my sleeping bag) as a pillow. If it's cold enough they freeze but sometimes the conductive heat from my body will warm them enough to prevent freezing.

    In the morning I put them on, dance and stamp around for a few minutes to warm my feet up and then it's go time. This is by no means the end-all answer, it's just what works for me.

  7. Sam – I hear you. Let's zoom out for a second. How do you prevent your seed water (for melting snow) from freezing at night? Do you put in in a thermos or sleep with a quart (or less) of pre-boiled water? Do you regulate your exertion level during the day at all to prevent over-sweating in your boots. Do you use gaiters and what kind? Do they make your socks damp? Focusing just on the boots can be misleading – and you need to really look at the whole system – I know you'd agree.

    The reason I didn't list your method above, is that I don't think a newbie will understand all of the factors that might make your technique work. Would you advocate your method on a BPL winter trip with someone who'd never done winter camping before?

    I've looked long and hard at your alternative this winter to get my gear weight down, and ended up backing away from it. So, I am really do want to know what you'd do on a UL school trip. Will Reitveld's awesome series on UL shoe systems for winter sent my head reeling.

  8. As I only have one pair of winter boots – and they have no removable liner – I have no choice but to stick them in the bottom of my bag – wrapped in a garbage bag. I throw in chem bag and I also wear my down booties in the bag. I find that if I do not wear my down booties my feet get cold at night (rest of body is fine). I only do 2 or 3 winter hikes – usually one or two nights have not cost justified dedicated plastic mountaineering boots. I will look at the Will Reitveld’s series on UL shoe systems for winter

  9. sleep with the boots/liners … put them in a bag with the mouth venting out …

    put a handwarmer of a hot nalgene in the bag

  10. I think that VBL and removable liners compliment each other rather than being a substitute for each other. They are really two different goals. Keep moisture out of the insulation and keep the insulation relatively warm overnight.

    I was bitter when I learned that the AMC hike leaders required PAC boots or Plastics but after a few winter overnights I understood why…

    If you are very concerned about someone losing toes, then a folding saw to facilitate prepping wood for making a fire might be in order.

    I have BAFFIN winter boots and they are full sizes only and run small. I wear a 9.5 and ended up needing a size 11. They are a bit less floppy than Sorel Pac boots, but not by much, IMO. I like them but I avoid trail that require crampons.

  11. Tom – I appreciate you sharing that. I remember your resistance on this issue.

  12. Like samh I use lightweight goretex boots for winter. But I just let the freeze overnight. It doesn't take long at all for them to thaw in the morning. Now it is critical to loosen the laces at night, otherwise you can't get your feet into frozen boots in the morning.

    To keep my water from freezing, I have put it in my sleeping bag, but usually I can just keep it under my bag. I'm more protective of my water filter and keep it in a dry bag inside my sleeping bag. I use a gravity filter and had my worst freezing experience with it on one the first nights in Georgia. I left the clean water bag outside overnight with about a liter in it. The next morning I had a liter brick of ice blocking the opening, so I couldn't filter water and had to carry the ice brick inside my jacket until it melted.

  13. Depending on where you're camping (above treeline) why don't you use a Kifaru or similar tipi with a wood stove? Then you can dry all of your gear out and stay warm.

  14. Pat – an interesting suggestion, but the group I'll be taking out has probably never used a tipi or a floorless shelter. I on the other hand use a pyramid tarp that's a lot lighter than a kifaru tipi, but regarding wood, I wouldn't count on finding any that's not buried under 3-6 feet of snow where were headed. Above treeline is also a moonscape. No wood at all.

  15. Some people have success with putting disposable heat packs in their shoes overnight. I've tried it twice and they didn't heat up until I put them in my pockets in the morning. Odd.

  16. That is strange Walter. I could see it happening only if you'd deprived the chem packs of oxygen. The heat is generated when the iron filings inside "rust".

  17. I found the little sock ones were useless when wearing boots because of the lack of oxygen. Gotta get some air to them to produce heat.

  18. I put lots of stuff UNDER my bag.

    Wet and/or lumpy stuff go under the air mattress or foam pad (and above the ground sheet), everything else in between the bag and the pad.

    For liners or tall leather boots, I lay them on their side and slip the tops under the mattress, one on each side, with the soles facing out. If I am sleeping on uneven (left-to-right) ground I put both boots on one side as shims to keep me from rolling.

    Everything I wore the day before and everything I am planning to wear in the morning go under me somewhere. Keeps them from freezing and adds extra insulation between me and the cold, cold ground.

  19. The second night, I kept the hand warmers in my sleeping bag for a while but they still didn't "ignite" until the next morning. Would be a good solution for short trips if it worked.

  20. Walter – What brand were you using? I've used chemical warmers (Grabbers brand) very successfully on some hikes (great when clenched above the femoral arteries) and they are part of my emergency kit in winter. I've never had a failure like you describe.

  21. Same brand. I wouldn't think it significant, except it happened twice with both boots, which makes four times. The second time, I put them in my pockets the next morning and they got very warm after a while, so they weren't duds.

    Maybe they exhaust the oxygen down in the boot and go dorment. Might need to lay the boots on their side for more air circulation, though I think the heat would get some convection going.

  22. The iron oxidation handwarmers have water in them. Mechanically when you activate them you mix the water and the dispersed iron and the reaction heats up. I wonder if you can freeze the handwarmer to where the water can't mix with the iron and thus the reaction doesn't happen? Of course once thawed (say in the morning when you've warmed up your sleeping bag or in a pocket as you're carrying them out), they'd warm quickly. (I doubt there is much of a freezing point depression from mixing the water with vermiculite and unless they use a very concentrated brine there won't be much freezing point depression from the small amount of salt added to the mix).

  23. If it's below freezing, take the liners out and put them in your bag. The hassle is that we all change into down booties when we arrive (mine fit inside my Koflach shells nicely), and then several hours later hop in our bags with the now-frozen liners.

    Such is life! I find I'm quite cold for the first couple of hours until the liners warm up, even when I heat the waterbottles. But what are the other options? There really aren't any, because it's not just about warming the boots, but also drying them out–which is why we have to put them in the sleeping bag. If all you're doing is heading down, well, maybe you can leave them out. But if you're hiking all day, I feel one really needs to bring them into the bag at night.

  24. I don’t suggest sleeping with boots in the sleeping bag. A 0 degree bag and warmer cannot evaporate the moisture and over multiple days will make your bag too wet.

    Try 2 long narrow waterbottles.

    Once you get to camp start melting water first off as you start building camp. Vent your feet by taking your foot out of the boot and letting vapor leave. As soon as you feel cold on your foot put it back in the boot. Keep shoveling and working on the shelter to keep warm. You should be venting all your layers with the heat you generate from building camp too.

    Once you have the melted snow to fill your watterbottles, let it come to a boil. Then one at a time, fill the waterbottle (hot! wear gloves) and swap your foot for the waterbottle quickly. Put dry socks on and down booties. This is your new footwear until morning.

    Put your moist sock in the top of your boots to keep heat in from the waterbottle. Then, pack the boots into your pack or a stuff sac and situate them sole up (heat rises, don’t let it escape). If the temp out is -10F or colder you really need to pile alot of snow on that pack with your boots.

    In the morning your boots should be around room temperature and still moist. You’ll want to use that water for your oatmeal and for your days water. Any other water will be frozen (unless you slept with it, which I can’t stand) and with the warm dry socks you slept in you can slip your foot into that boot and be pretty comfortable.

    You’ll save time in the morning not having to melt more water and you’ll possibly have slept well. If your friends snore, or we’re on some insane windy peak, I suggest ear plugs for that. Sleep well! Very important. You’ll be charging while your friends fumble around cold.

    Basically, the methodical proceedure helps keep you from getting in your sleepingbag too early which often happens when winter nights often start just after 5pm.

    If anything I suggest knowing your fuel consumption and practice melting water. I sometimes want to take my own stove so I can melt water and make hot drinks and food at my own pace.

    Cheers!

  25. P.S. I’ve used snowboard, AT, and basica mountaineering boots. So often there is a tall part of the boot up the shin. Short hiking boots and shoes…at your own risk :)

  26. sleeping inn your boots is not the only way to keep them from freezing. I put hand warmers in my heavy socks, then stuff them into my boots. After, I put my coat over them. 12 hours later, my boots are still warm

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