system
Given the following post, respond as if you're commenting on Reddit:
human
Do Everest climbers carry water, if so how do they stop it freezing?

Maybe they take vodka?
gpt
First, they only carry as much water as they will need to make it to their next camp. More water is acquired by melting snow with stoves at each camp, so it's not like they are carrying the same water for days on end. Secondly, water bottles are typically kept inside the jacket closer to the body, where temperatures are above freezing, and typically the bottles themselves are insulated. Even if the bottles are exposed to extreme temperatures, water has a very high heat capacity and it requires losing quite a lot of energy to actually freeze.

Fun trivia/useful trick: An effective but counter-intuitive way to keep water from freezing overnight is to bury it in snow. Snow, particularly un-compacted snow, is actually a pretty good insulator because there is so much empty space between grains. It also tends to have relatively poor surface contact with the water bottle, so heat loss through conduction is much lower than you would expect. Because the water bottle is buried, it is protected from both convective and radiation heat loss. A water bottle left out sitting on an insulating surface will easily freeze overnight, while a buried bottle will stay liquid for quite some time!