Winter is coming [in the northern hemisphere]. An important skill is treating and preventing cold exposure, especially if a person is disabled and on the ground. The ground steals heat through direct conduction and by absorption of moisture.
Always go out well fed, include plenty of protein, copious warm hydrating liquids, and fats. Together these break down in a heat generating reaction as well as providing large amounts of energy for more heat generation.
Have a way to make a warm drink. A Thermos is skimping, better a small stove that is easily lit and kettle that will let you melt snow and make hot water to drink, this saves your body from having to heat
your drinks and also raises your core temperature if you get chilled or worse. Cold drinks bring down body temperature and the metabolism required to heat it to body temperature nearly requires as much water as you are consuming, un-melted snow is actually hydration negative due to the metabolism [required] to bring it to body temperature.
Insulate from the ground, dry grass leaves, seat pad foam, clothing, whatever. The ground will steal your body heat quickly.
Share warmth with a friend or more, huddle, hug, stack up as injuries allow.
Protect the heat loss areas. Cover first the head, then armpits, groin, trunk, and finally the extremities.