Extreme cold, wind chill, frostbite and hypothermia
Extreme cold can cause frostbite and hypothermia in minutes. Cover your nose, ears, cheeks, chin, fingers and toes, dress in loose layers and stay dry. Numb, white or waxy skin can mean frostbite. Shivering, confusion, slurred speech or drowsiness can mean hypothermia, and a body temperature below 95°F is an emergency: call 911.
Information may be delayed or incomplete. Always verify with official sources and follow local officials.
“People exposed to extreme cold are susceptible to frostbite and can succumb to hypothermia in a matter of minutes.”National Weather Service, Cold Weather Safety
What wind chill means
The National Weather Service says wind chill is how cold people and animals feel when they're outside. Wind pulls heat away from your skin, so it feels much colder than the thermometer says (NWS: Understanding wind chill).
“If the temperature is 0°F and the wind is blowing at 15 mph, the wind chill is -19°F. At this wind chill temperature, exposed skin can freeze in 30 minutes.”National Weather Service, Understanding Wind Chill
- Frostbite needs freezing air. The NWS says you can only get frostbite if the actual air temperature near your skin is below freezing. Wind chill alone can't do it, but you can still get hypothermia.
- Wind chill doesn't apply to things. Pipes and car radiators only cool to the actual air temperature, just faster in the wind (NWS).
- Be extra careful with kids and older adults. The NWS says wind chill testing was done on adults, so be even more cautious with children, older people and anyone in poor health.
Cold alerts
The National Weather Service now issues Extreme Cold Warnings and Cold Weather Advisories (these replaced the older Wind Chill Warnings and Advisories). Your local NWS office sets the levels. In the Rochester, NY area, for example, an Extreme Cold Warning means the temperature or wind chill is expected to fall to -25°F or lower. Cold is dangerous with or without wind (NWS).
Frostbite: how to spot it
CDC says frostbite most often hits the nose, ears, cheeks, chin, fingers and toes, and it can cause permanent damage. Severe cases can lead to amputation (CDC: Preventing frostbite).
“If you notice redness or pain in any skin area, get out of the cold or protect any exposed skin—frostbite may be beginning.”CDC, Preventing Frostbite
- A white or grayish-yellow patch of skin
- Skin that feels unusually firm or waxy
- Numbness. CDC says people often don't know they have frostbite until someone else points it out.
Hypothermia: how to spot it
The National Weather Service says hypothermia happens when the body loses heat faster than it can make it. CDC says it can happen even above 40°F if someone gets wet from rain, sweat or cold water and gets chilled.
- Adults: shivering, exhaustion, confusion, fumbling hands, memory loss, slurred speech, drowsiness (CDC)
- Babies: bright red, cold skin and very low energy (CDC)
“Hypothermia is an unusually low body temperature. A temperature below 95 degrees is an emergency.”Ready.gov, Winter Weather
What to do while you get help
Hypothermia is a medical emergency. Call 911. CDC's steps for hypothermia or frostbite:
- Get medical care as soon as you can.
- Get them into a warm room or shelter.
- Take off any wet clothing.
- Warm them under dry layers of blankets and clothing. Ready.gov says to warm the center of the body first: chest, neck, head and groin.
- For frostbite, use warm, not hot, water that feels comfortable on unaffected skin. If there's no warm water, use body heat, like tucking frostbitten fingers in an armpit.
CDC also says: don't rub or massage frostbitten skin, don't walk on frostbitten feet unless you have to, and don't use a heating pad, heat lamp, stove, fireplace or radiator to warm it. Numb skin burns easily.
Staying safe in extreme cold
- Stay inside when it's extremely cold. If you have to go out, CDC says to wear a hat, a scarf or knit mask over your face and mouth, mittens or gloves, a water-resistant coat and boots, and several loose layers.
- Stay dry. Wet clothes and sweat pull heat away fast (CDC).
- Know who's at higher risk. CDC names older adults without enough food, clothing or heat, people outdoors for long periods, people who drink heavily or use drugs, and babies sleeping in cold rooms.
- Limit time outside and watch for frostbite and hypothermia. Avoid overexertion shoveling snow (Ready.gov).
- Heat your home safely. Never use a gas stove or oven for heat, and keep generators and grills outside, away from windows (Ready.gov). See Space heater and home heating safety.
- If heating bills are a problem, Ready.gov points to the Low Income Home Energy Assistance Program (LIHEAP). You can also call or text 211 for local help.
Common questions
What is wind chill?
The National Weather Service says wind chill is how cold people and animals feel outside. At 0°F with a 15 mph wind, the wind chill is -19°F, and exposed skin can freeze in 30 minutes.
What are the signs of frostbite?
CDC says redness or pain may come first, then a white or grayish-yellow skin area, skin that feels unusually firm or waxy, and numbness. People often don't notice it themselves because the skin is numb.
What are the signs of hypothermia?
CDC lists shivering, exhaustion, confusion, fumbling hands, memory loss, slurred speech and drowsiness in adults, and bright red, cold skin and very low energy in babies. A body temperature below 95°F needs medical attention right away.
Can you get hypothermia when it's above freezing?
Yes. CDC says hypothermia can happen above 40°F if a person gets wet from rain, sweat or cold water and becomes chilled.
Should I rub frostbitten skin to warm it up?
No. CDC says not to rub or massage frostbitten skin, and not to use a heating pad, heat lamp, stove, fireplace or radiator, because numb skin burns easily. Use warm, not hot, water and get medical care.
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