Winter Camping Water Purification Guide
DON'T EAT SNOW
Eating snow will only lower your core body temperature and make you more susceptible to hypothermia.
Drink Water or Die
Yes, even in the harsh cold winter it is necessary to hydrate. For dehydration is a real threat to the backpacker during the snowy months too. So, start pumping water from your filter into your camelbak bladder and ... oh wait a minute, scratch that. That's right, after your filter freezes and cracks you won't be able to purify water anymore, but that's okay your water bladder is now a frozen block of ice conveniently located on your back. The winter backpacker must change their tactics for gathering, purifying, and carrying water.
So much water does a person need?
A study by the Institute of Medicine concluded that an adult male requires about 3 liters of water per day, and a woman must have an intake of 2.2 liters per day.
However, with increased energy output, sweating, and water loss through heavy respiration the winter hiker requires additional water intake. Though everyone's bodies have different requirements, many mountaineers agree that you need to drink about 3/4 to 1 liter of water for every hour of trekking through the snow.
Yes, that's a lot of water!
A good strategy, is to be well hydrated for several days before venturing into the cold. If you start mildly dehydrated - things are only going to get worse. Many backpackers also pound an electrolyte-rich drink just before heading out on the trail. Also, make sure your water bottles are topped off (and unfrozen) before heading out.
Most importantly, watch your pee! Yes, watch for the color variations in your urine; you want it to be as clear as possible. If your pee is that dark yellow, STOP and drink water.
If you are dehydrated, STOP, make yourself comfortable and safe. Start sipping water and eat some salty electrolyte-rich food. You may want to make camp for the night. Don't start hiking until, you are well hydrated.
Know the Signs of Dehydration
Symptoms of Dehydration from Mayo Clinic:
- Dry sticky mouth, dried up mucous membranes
- Dry skin
- Lack of elasticity in skin
- Decreased urination - and dark urine
Simple, right? Just go down to the lake, dip, and voila - water is gathered. Well, maybe - but usually is goes something like this.
"There was a lake here, wasn't there?"
"All I see is a big snow field; check the GPS again."
"Okay, according to this we should be right in the middle of it."
"You're a moron, give me that thing! Hey, do you hear a weird cracking sound? "
Yep, finding open water in winter can be difficult and when you start looking out on the ice, it can be dangerous. And in the backcountry accidents on ice are usually deadly.
Though snow melting is a fantastic way to "make water," it has a high fuel cost and is time intensive. Therefore, whenever an open source of water can be safely accessed, it is more energy and time efficient.
First of all, be careful whenever venturing onto or nearby ice. Test the ice with a trekking pole and try to stand on logs or rocks as you dip or chip into the ice. Again, standing in the middle of a pond, hammering on the ice with an axe may not be the best idea.
Often fast moving streams are good sources of easily accessed water as the ice generally isn't too thick.
Extend your reach by attaching your water bottle to the end of your trekking pole. To do this use a small piece of para cord to tie the bail of your wide-mouthed nalgene to the end of your trekking pole. For the knot-challenged, use a carabiner to clip the canteen to the hiking pole wrist strap. Sometimes the bails wear out on nalgenes, so tie a small piece of para cord below the threaded lip for water dipping.
If you plan on melting snow and cooking, plan on carrying about 8 oz of fuel per person per day for your white gas stove. Note: stove fuel economy differs between models so field test your stove before using it in the backcountry.
Tips for Melting Snow
Making water is simple, we all know the formula just create a covalent molecular bond between one oxygen and two hydrogen atoms - easy, duh. I'm not sure exactly how to do that though, so try making water by melting snow.
The advantage of melting snow is that melted snow is usually safe to drink, but remember don't scoop yellow or pink snow to put in your pot. To be safe, all water should be considered contaminated.
You could bring the water up to a boil; however that takes time and will increase fuel consumption. A more energy efficient way of making sure melted snow is safe to drink, is to filter large particulates out with a bandana or coffee filter into a water bottle, then treat the water chemically or with a UV lamp.
How to Melt Snow:
- Set stove up in a safe level area out of the wind. Compact snow underneath for a steady platform.
- Gather large amount of clean snow - a garbage bag works well. If you do have a garbage bag, gather snow in the morning and leave it in the sun to start a solar melting process.
- Erect wind screens, prime, and light stove.
- Place small amount of water in cooking pot and place on stove. The water will stop your pot from scorching as well as speed up the melting process. Keep about an inch of water in the pot at all times during the melting process.
- Start scooping snow into the pot. Be sure to keep pot lid on as much as possible to conserve fuel.
- As snow melts, keep on adding more snow to the pot. Depending on the denseness of the snow, it may take up to 10 quarts of snow to produce 1 quart of water.
- Stir the snow into the melted water with a stick to speed the meting process.
- Remove water from pot with a water dipper (AKA cup) and pour into water bottles.
- Filter out particulates (usually pine needles) pour the water through a bandanna or a coffee filter. The MSR mug mate coffee filter works great.
Melting Snow with MSR Reactor
Many 3-season backpackers rely on water pumps to filter their water; however, in winter filters can be a bad idea. What happens in freezing temperatures, is that residual water freezes inside the filter mechanism resulting in blown seals and cracked housings. The only real way to depend on a filter in freezing temps is to dry it out as much as possible and then keep it from freezing by carrying it in your jacket.
Chemical Water Purification
Chemicals are a great way to treat winter water, however most treatments are ineffective in cold water. Often water must be heated, in order for the chemicals to do their magic. One great method, is to melt snow to the point of "slightly warm" and then use chemicals. This practice requires less fuel and increases the effectiveness of your treatment.
One of the most popular winter water treatments is Aquamira. Aquamira is a two part chlorine dioxide treatment which neutralizes waterborne pathogens without an aftertaste in about 30 minutes. Best of all, Aquamira works better in colder water temperatures than traditional iodine tablets.
Though Aquamira is freeze-thaw stable, it can still freeze. In extremely cold temperatures, place both bottles inside your parka to keep them from freezing.
Using UV light to purify water
In the past few years, using UV light to purify water has become a lightweight and popular way to treat water. These battery powered devices, use UV light to disrupt the DNA of microorganisms and render the little water beasties harmless.
SteriPEN is the leader is producing travel sized UV lamps for rugged backcountry use. Some models have solar charging capabilities so you don't have to worry about batteries for extended trips.
So how do you use a SteriPEN? Though each model differs, generally you turn on the switch, plunge the pen into the water, then stir until the light goes out (usually about a minute). After that, there is no wait and no taste - just drink.
The UV light does not purify contaminated water droplets that may be on the bottle lid or threads, so be careful to clean the threads before placing your lips on the container to drink.
Storing Water in Winter
So where do you put the water after you gathered and purified it?
Hydration bladders are outstanding during the warmer months, however in the winter the bladder, the tube, and the bite valve can freeze easily. Camelbak does sell a thermal control kit to use with their bladders, but the neoprene insulation doesn't withstand the most extreme of temperatures. Remember after taking a sip, to blow back into the tube to clear the hose; the hose is usually the first thing to freeze. Generally winter backpackers avoid hydration bladders because of the difficulty in keeping them unfrozen.
Specially made insulated water bottle holders and wide mouthed water bottles are the thing to use while winter backpacking. For example, the Water Bottle Parka from Outdoor Research is a staple in mountaineering and are practically indestructible.
If economy is the hiker's primary need, then insulate water bottles with an old wool hiking sock. Sock gnomes never take socks in pairs, so most backpackers have a mismatched sock or two in their sock drawer.
The crafty backpacker can also make their own insulated water bottle cover with an old piece of closed cell foam and some glue.
Most backpackers and mountaineers opt to keep water bottles from freezing at night by placing bottles in their sleeping bag. One way to keep warmer at night is to fill a water bottle with hot water and put it in your sleeping bag.
Because snow is an excellent insulator, water bottles can also be buried in the snow to prevent them from freezing. Burying water is a good technique when dealing with large amounts of group water.
What is your favorite method of having water for winter backpacking?
Other Winter Backpacking Articles
- Crossing the Gully: An Adirondack Winter Adventure.
Outbound Dan Human recounts the true story of a dangerous adventure in the Adirondack backcountry. Though it started off as a simple solo snowshoeing trip, a momentary lack of safety protocol pits him against potential death.
- Winter Backpacking and Hiking Gear List
Outbound Dan Human shares his winter backpacking gear list for backpacking in the Adirondack High Peaks.
- How to Start Snowshoeing: Winter Hiking on Snowshoes
Snowshoeing is a fun way to explore the snow covered backcountry. If you ever wondered about how to start walking on snowshoes, getting started is easier than you think. Experienced snowshoer, Outbound Dan Human, offers advice on selecting and gettin
This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.