When exposed to very cold temperatures, the skin and underlying tissues may freeze, resulting in frostbite. The areas most likely to be affected are the hands, feet, nose, and ears.

Frostbite is distinguishable by the hard, pale, and cold quality of the skin that has been exposed to the cold. As the area thaws, the flesh becomes red and painful. If your fingers, ears, or other areas are frostbitten, get out of the cold. Warm your hands by tucking them into your armpits; if your nose, ears, or face are frostbitten, warm the area by covering it with dry, gloved hands. Do not rub the affected area. If numbness remains during warming, seek professional medical care immediately. If you are unable to get immediate emergency assistance, warm severely frostbitten hands or feet in warm--not hot--water. (The water should be between 100 and 105 degrees Fahrenheit).

Heat exhaustion occurs when your heart and vascular system do not respond properly to high temperatures. The symptoms of heat exhaustion resemble shock and include faintness, rapid heartbeat, low blood pressure, an ashen appearance, cold clammy skin, and nausea. If you suspect heat exhaustion, get the person out of the sun and into a cool spot. Lay the person down and elevate his or her feet slightly. Loosen or remove most or all of the person's clothing. Give the person cold (not iced) water to drink, with a teaspoon of salt added per quart and call 911

The main indication of heat stroke is a fever of 105 degrees Fahrenheit with hot, dry skin. Other signs include rapid heartbeat, rapid and shallow breathing, either elevated or lowered blood pressure, and confusion or unconsciousness. If you suspect heat stroke, get the person out of the sun and into a cool spot. Cool the person by covering him or her with damp sheets or spraying with water. Direct air onto the person with a fan or a newspaper, and call 911