If you get wet from rain, snow or sweat, change into clothing that is dry. Wet clothing loses its insulation value and extracts body heat 240 times faster than dry clothing. Wool clothing and blankets are preferred. Cotton clothing, particularly denim, retains water. Woll clothing is insulating, water resistant, and keeps your body warm even if it is wet.

Covering your head is vital as you can lose up to 80% of your body heat through your head. A knitted wool stocking hat is good.

Feet can be kept warm by wearing wool socks and wearing two pair if your shoes are large enough. A towel could also be wrapped over shoes and duct-taped on.

Several thin layers of loose-fitting clothing retain body heat and can be removed easily if body starts to perspire and/or you are chilling. Water & wind resistant outer clothing with a hood. Also, scarf or towel to cover your mouth to keep cold air from your lungs.

Two or more people huddled together inside two sleeping bags zipped together will be warmer than each in separate sleeping bags. A smaller bag can also be placed inside a larger-sized one.

If trapped in your car during a snowstorm, run heater 10 minutes every hour. Make sure the exhaust pipe is not blocked by snow and open one window a crack to allow ventilation.

Good in wind or rain. Put a wool blanket between you and the Mylar blanket, if possible.

You can also use socks filled with rice/beans and tied shut. Heat the packs/socks in a fire or coals. They will maintain heat for a period of time. Rocks or bricks can also be heated thoroughly, then carefully wrapped in towels or newspapers.

Leaves, newspaper, straw, etc. (stuffed between two layers of clothing). Tie your shoe laces around the cuffs of your pants to hold material in. If you were trapped in a car during a snowstorm, use the stuffing from the seat cushions.

This can be worn as a rain jacket or can insulate the body if stuffed with dry leaves or grass

Do you have any more ideas for alternate heat sources? Share them in the comments below!
***Modified from a church handout, no sources credited***