You are right and wrong. Right in that up in your area with high temps below 0 is very, very, very cold. But having said that, temps below 0°C are cold. If someone doesn't have a heat source it can be life threatening. Hypothermia can set in easily without a fire or heat source. Say a person has their car slide off into a ditch in western North Carolina in a remote area. Temps down to low 30s. If forced to stay the night out there than they had better have a heat source. Whether that be heat from the cars heater or a fire made from dry wood outside. It wouldn't take long for hypothermia to set in with temps around freezing. Now up in your area that time is greatly reduced obviously due to it being -10°F during the daytime and -25 to -30°F at night currently. But even temps around 32 will cause problems too. Heck even if we are dumped into water out in the ocean that is in the low 70s we will become hypothermic in time. Not has fast obviously if one sent over board in the Bering Sea.... But it still will happen. Our ability to maintain homeostasis and body temperature is not as guaranteed as we like to think it is.. Things can and still do happen. I know of a man who died from hypothermia and cold exposure. He wandered from his house due to dementia and couldn't find his way back. Temps in the low 30s and upper 20s that night. His body wasn't found for 2 yrs. About a mile from his house. If he could've or thought to make a fire he would have made it.