Winter camping in the New Zealand mountains is an easier proposition than it is in many mountain ranges overseas. Nonetheless, the risk of hypothermia should not be taken lightly, and being adequately prepared will at least make the difference between an enjoyable experience and a miserable one.

In the first post in this series on Alpine winter camping, we looked at how to pitch a tent in snow. In this second post, we discuss a few tips and tricks on how to stay warm and comfortable.

Warm clothing and sleeping bag

Starting with the obvious, you’ll want plenty of warm layers and a warm sleeping bag. Most importantly, you’ll want dry layers to change into after setting up camp – having your sweat dry out on you in freezing conditions is far from pleasant, and sucks heat out of your body.  Discussing the layer system goes beyond the scope of this post, but at least a set of next to skin thermals (top and leggings), a warm fleece and a pair of pants, a thick pair of socks, a warm hat, a down jacket and a windproof shell are highly recommended.

A word of caution about expensive down clothing designed for Himalayan or Antarctic expeditions. Yes it is super warm and comfortable. No it is not necessary in New Zealand conditions. And generally, it is not waterproof since it is designed to be used in cold and dry climates. Our snow is typically wet. Any down garments that get saturated with humidity lose their insulating properties.

A warm sleeping bag is a must when camping in the alpine in winter. A comfort temperature rating between -12C and -16C is adequate. Some people prefer synthetic sleeping bags on the grounds that a down sleeping bag doesn’t keep you warm if it gets wet. I find a tent keeps me dry enough to justify the comfort of a down sleeping bag. Maybe this is a topic that is best debated in a separate post.

Down-filled sleeping bag liners weighing less than 500gm are readily available and improve a sleeping bag’s temperature rating by about 10C. This can be an excellent solution if you have a three-season sleeping bag already and don’t want to invest in an expensive winter one.

What about a hottie?

Spooning with a hot water bottle inside your sleeping bag makes for a warm night. Sometimes too warm, since the heat cannot escape to the sides as it does under blankets. I usually fill a Nalgene bottle with warm or hot water before going to sleep and take it into my sleeping bag. This has two advantages. First it keeps me warm. Second, the water bottle doesn’t freeze overnight, and I have drinking water at a pleasant temperature the next morning.

A word of caution: Nalgene bottles take boiling water without deforming. Copycat bottles by other brands may not. Some plastics become soft and moldable at high temperature and can easily break if accidentally rolled on during the night. If in doubt, test your bottle at home beforehand. It is not a good idea to conduct physics experiments with water in your sleeping bag while alpine camping in winter.

As the water inside the bottle cools down, the air pressure inside the bottle drops. The differential in pressure may cause the lid to lock tightly, making it impossible to open again. If this happens, warm up the bottle in a pot of hot water to unlock the seal.

If you are not alone in your tent, spooning with a friend is just as effective as a hot water bottle – and it might be more pleasant. If it’s three of you in a tent, the place in the middle is worth fighting for.

For your fingers and toes

In cold conditions blood flow gets concentrated around our vital organs to keep them working properly and to keep the core body temperature up. Our extremities (toes and fingers) may lose circulation and become susceptible to frost-bite. Warm gloves and boots are especially important and deserve a separate mention.

Gloves are such a critical piece of equipment, most people carry at least two pairs whenever they head into the alpine environment. Some people carry three pairs, and I cannot fault them. Just don’t skimp and go with one pair only – think about the consequences of losing a glove (a very easy thing to do), or getting it soaking wet (another very easy thing to do). I usually carry a pair of boiled wool mittens, and a pair of leather ice climbing gloves. The former are unbeatable for warmth except in windy conditions, whereas the latter are better for dexterity.

Gloves used by freezer workers are highly rated. They can be bought at any work safety store, they are cheap compared to technical mountaineering or ski gloves, they are warm, durable and allow good finger dexterity.

Personally I do not recommend so-called ‘photography gloves’ or similar, with flip finger caps. They are expensive and never as warm as regular gloves. The finger opening lets cold air, snow or water in. And to be honest, I am able to fully operate my camera and perform most other tasks while wearing regular ice climbing or ski gloves.

Boots are another rather important piece of equipment. When trudging through snow all day, you really want a pair of boots that are a) fully waterproof, and b) warm. In winter conditions I like wearing a pair of mountaineering boots with separate inner booties, no matter if I’m planning a technical climb on crampons, a snow shoeing trip on mellow open tops, or if I am just setting up camp in the snow to take photographs. My toes are always grateful for the additional warmth. If you are ski-touring, it goes without saying, you’ll be wearing ski touring boots instead. And a pair of gaiters to keep snow out of your boots is helpful in all circumstances, too.

Finally, a word about river crossings in winter. In New Zealand we generally walk across rivers with our boots on. Well, except in winter, when it’s legit to go out of your way to keep dry feet. Soaking wet boots freeze solid at night, and the saying of putting a pair of ice blocks on your feet the next morning may become true to the letter. Just remember to carry a spare pair of shoes or jandals to cross any rivers, since doing it barefoot is likely to result in injury.

Boots and wet clothing at night

You’ve set up camp, had a warm meal (more on this in a separate post) and are ready to go to sleep. What to do with the clothing you’ve be wearing all day, and with your boots?

As to the clothing (next to skin thermals and socks), assuming it’s damp from sweat but not soaking wet, I simply keep it inside my sleeping bag. The next morning it will be mostly dry, and warm enough to put on again without screaming in pain.

As to the boots, different people may have different solutions, but by all means they are best kept inside the tent. Not in the vestibule, not in your pack, and not outside. After taking them off your feet, pull them wide open – if they do freeze solid during the night, at least you’ll still be able to put them on the next morning.

As to where in the tent you should keep your boots, again, it’s up to you. I have slept with my boots on – very uncomfortable and not recommended. I have slept with my boots wrapped in a plastic bag, inside (and at the bottom of) my sleeping bag – very uncomfortable again, unless you are a short person with a long sleeping bag. Most often, I use my boots as a pillow under a fleece or a jacket, or I store them somewhere next to my sleeping bag or under my feet.

And if your boots are wet then freeze so hard you can’t slip your feet back in, pour a billy of boiling water onto them before putting them on. A rather extreme solution, yes, but better than using what little heat may be left in your toes to melt the ice. Starting the day with a pair of warm, wet boots is better than starting the day with a pair of frozen solid, wet boots.

 

Between your body and the snow

Nowadays we are spoilt for choice between a multitude of inflatable sleeping mats. Which one to choose? One simple way to compare two or more sleeping mats is to look at the footprint left in the snow after taking down camp. The deeper the footprint, the more snow was melted by the person who slept on it. This indicates a lower quality sleeping mat, or a warmer sleeper.

Alternatively, you might get a salesman in an outdoors shop too recite the R-value of every single sleeping mat in their store. The R-value of a sleeping mat is a number that indicates its insulating ability. The higher the R-value, the lower the heat loss through the sleeping mat. But there is a catch: the R-value is not an objective measurement. R-value scales differ between manufacturers, and are not directly comparable. Do not assume that a sleeping mat with R-value 6 by manufacturer A is going to insulate better than a sleeping mat with R-value 5 by manufacturer B! Below are two examples of commonly used R-value scales:

 

As a rule of thumb, for winter camping you’ll want a sleeping mat with an R-value of 3 or higher.

Now for a very important disclaimer: the R-value refers to a fully inflated sleeping mat. Duh. I know. We all know the story of the Princess and the Pea, right? Well, at one stage I forked out $400 for an ultra-light sleeping mat rated R = 5.7. Sounds fantastic. Except that a frozen pea on flat snowy ground is enough to puncture said fantastic sleeping mat. A very cold night is guaranteed. One year and twenty punctures and repair works later, I threw out the not-so-fantastic sleeping mat and replaced it with one by a different manufacturer. R = 5 (different scale compared to the above R = 5.7), weighs 1kg (do not believe in miracles!), and has two separate air chambers, so if one goes flat the other one still gives you R = 2.5. At present I’m sleeping much better.

If you do end up with a punctured sleeping mat (R = 0), put anything you have between your sleeping bag and your deflated mat: your (empty) backpack, any spare clothing, a rope spread out in coils, or any otherwise useless object that somehow ended up in your pack. If you are really keen, you can carry an old foam mat to go under your inflatable one. It will protect the latter from puncturing, while adding to its insulation at the same time.

How big is your bladder?

Winter nights are long. When faced with the idea of walking out in the cold, some people end up testing their bladder’s capacity to its very limit. More often then not, I have to go outside and water the stars at least once.

Guys, if you are in a tent by yourself, or with someone towards whom you don’t feel any inhibitions, you can pee in a bottle or in a pot while lying down, then empty the container outside, all without having to leave your sleeping bag. Gals, you can do it, too – but you need a shewee, having practiced its use beforehand.

Safe alpine camping

Some general advice to make your winter camping experience safer:

• Before you go out, always check weather forecasts and avalanche bulletins.
• Leave intentions with someone trusted, and carry some means of emergency communication.
• Go with friends. If you have never camped in the snow before, it might be a good idea to learn from someone experienced.
• Join a club. Many clubs teach winter camping skills as part of their basic snowcraft courses.