| What it is | Core temp below ~95°F (35°C) |
| Causes | Cold, wet, wind; exhaustion |
| Early signs | Shivering, clumsiness, confusion ('umbles') |
| Severity | Life-threatening if untreated |
Hypothermia is a dangerous drop in core body temperature below about 95°F (35°C), caused when the body loses heat faster than it can produce it — often from cold, wet, and windy conditions. Early signs include intense shivering, clumsiness, and confusion; severe hypothermia is life-threatening and requires rewarming and urgent medical care.
This is general educational information, not medical advice. In an emergency, seek professional medical help and call for rescue.
Prevention
Stay dry, manage layering, eat and drink, and carry extra insulation from the Ten Essentials. The related cold injury is frostbite.
Frequently asked questions
What are the signs of hypothermia?
Early hypothermia shows as vigorous shivering, cold and pale skin, and the 'umbles' — stumbling, mumbling, fumbling, and grumbling — reflecting impaired coordination and judgment. As it worsens, shivering may stop, confusion deepens, and the person becomes drowsy and unresponsive, which is a medical emergency.
How do you treat hypothermia in the field?
Stop further heat loss: get the person out of wind and cold, remove wet clothing and replace with dry insulation, and add a hat and a windproof/waterproof layer. Give warm, sweet drinks if fully alert, add external heat to the core, and handle them gently. Severe hypothermia (no shivering, altered consciousness) needs urgent evacuation and professional care.
How do you prevent hypothermia?
Stay dry and manage layers to avoid both sweating and chilling, eat and drink regularly to fuel heat production, avoid cotton, carry extra insulation and a shelter (part of the Ten Essentials), and watch yourself and partners for early signs. 'Cold, wet, and windy' are the conditions to respect even in mild temperatures.
Sources
- Hypothermia & cold — CDC
- Cold injuries — Wilderness Medical Society
- Cold-weather safety — National Park Service