https://www.scouting.org/health-and-safety/safety-moments/hypothermia/
Hypothermia is an abnormally low body temperature that is dangerous and potentially fatal if not properly cared for. Hypothermia most often occurs when individuals are exposed to extremely cold temperatures for extended periods of time. However, it can also occur in warmer environments in situations such as wearing wet clothing in windy conditions, becoming chilled from being in the rain for an extended period, or being submersed in cold water. Planning is essential before a trek or outing to make sure you are prepared for possible changes in environmental conditions.