Right now, many people in Texas have power but no water and are turning to melting snow to have something to drink or wash in. This technique does work—as wintertime campers know well—but there are a few tips that will help you do the job efficiently.
Choose a wide pot
While you can melt snow in any pot (even a crock pot), the wider it is, the more snow you can bring into direct contact with the hottest part of the pot.
Find clean snow
Whatever is in the snow you melt will become part of your water, so make especially sure to find clean snow if you’ll be drinking it or cooking with it. Boiling can kill microorganisms, but it won’t get rid of dirt or chemicals.
Mountaineer Andy Lewicky writes that he avoids any snow under tree branches, and that he likes to avoid the snow at the very surface. Look for any visible signs that the snow is contaminated, like dirt or the infamous “yellow snow” (urine).
Note that you will need a lot of snow. Your pile will shrink to almost nothing as you heat it, so collect more than you think you’ll need.
Only melt a small amount to start
You melt snow by adding snow to water, so you need to start with water. If you have a cup or so of plain water, put that in your pot. If not, start with a few handfuls of snow and don’t add any more until that has melted.
The water in the bottom of the pot acts to conduct heat and protect your pot from burning. If you disregard this advice and pack the pot full of snow, it could take a long time and waste a lot of fuel to actually melt it.
Once you have some water warmed up in the bottom of the pot, add snow a little bit at a time.
Use a lid
Once the water starts heating up, it will start to turn into warm water vapor. Keep a lid on your pot and you’ll essentially steam the snow, melting it faster.
Don’t boil it if you’re not drinking it
What is your goal? If you want to ensure it’s safe to drink, go ahead and heat it to a roiling boil, and let it boil for a full minute. (Melted clean snow is generally considered safe by campers, but the CDC recommends boiling it. Better safe than sorry.)
But if you just need water for washing, or if you have another way of treating the water to be sure it’s safe to drink, save yourself some time and fuel. To melt snow, the water only has to be warmer than the snow; lukewarm will do.
Consider filtering the finished water
If drinking snow gathered from your yard icks you out, you can filter or treat the water as you would while camping. (REI has a guide to filters and purifiers here.)
If you finish melting the snow and discover dirt or bits of vegetation in it, you can remove those by passing the water through a coffee filter.