Extreme Cold Safety

Extremely cold air comes every winter but the arctic air, together with brisk winds, can lead to dangerously cold wind chill values.

Watch, Warning and Advisories
  • Wind Chill Advisories are issued when low wind chill temperatures are expected but will not reach local warning criteria. Extremely cold air and strong winds will combine to generate low wind chill readings. If you must be outside, take precautions against frostbite and hypothermia.
  • Wind Chill Watches are issued when there is the potential for a combination of extremely cold air and strong winds to create dangerously low wind chill values.
  • Wind Chill Warnings are issued for a combination of very cold air and strong winds that will create dangerously low wind chill values. This level of wind chill will result in frostbite and lead to hypothermia if precautions are not taken. Avoid going outdoors and wear warm protective clothing if you must venture outside.


Cold Stress

just like during the summer months, extreme temperatures can be dangerous to outside workers in the winter months. Environmental cold can affect any worker exposed to cold air temperatures and puts works at risk of cold stress. When wind speeds increase, the cold air temperature feels even colder, increasing the risk of cold stress to those working outdoors. Types of cold stress include trench foot, frostbite, and hypothermia.


Risk factors for cold stress include:

  • Wetness/dampness, dressing improperly, and exhaustion
  • Predisposing health conditions such as hypertension, hypothyroidism, and diabetes
  • Poor physical condition


Employers and employees should know how to recognize the environmental and workplace conditions that can lead to cold stress.

Supervisors should

  • Monitor workers physical condition
  • Schedule frequent short breaks in warm dry areas, to allow the body to warm up
  • Schedule work during the warmest part of the day
  • Use the buddy system (work in pairs)
Types of Cold Stress

Immersion/Trench Foot– Trench foot is a non-freezing injury of the feet caused by prolonged exposure to wet and cold conditions. It can occur in temperatures as high as 60 degrees F if feet are constantly wet. Injury occurs because wet feet lose heat 25 times faster than dry heat.

Symptoms of trench foot include: Reddening skin, tingling, pain, swelling, leg cramps, numbness, and blisters.


First Aid

  • Call 911 immediately in an emergency: otherwise seek medical assistance as soon as possible.
  • Remove wet shoes/boots and wet socks.
  • Dry the feet and avoid working on them.
  • Keep affected feet elevated and avoid walking. Get medical attention.


Frostbite- Frostbite is caused by the freezing of skin and tissues. Frostbite can cause permanent damage to the body, and in severe cases can lead to amputation. The risk of frostbite is increased in people with reduced blood circulation and among people who are not dressed properly for extremely cold temperatures.

Symptoms of frostbite include: Reddened skin develops grey/white patches in the fingers, toes, nose, or ear lobes; tingling, aching, a loss of feeling, firm/hard, and blisters may occur in affected areas.


First Aid

  • Follow the recommendations described below for hypothermia
  • Protect the frostbitten area, e.g., by wrapping loosely in a dry cloth and protect the area from contact until medical help arrives.
  • DO NOT rub the affected area, rubbing causes damage to the skin and tissue.
  • DO NOT apply snow or water. Do not break blisters
  • DO NOT try to re-warm the frostbitten area before getting medical help. If a frostbite area is rewarmed and gets frozen again, more tissue damage will occur. It is safer for the frostbitten area to be rewarmed by medical professionals.
  • Give warmed sweetened drinks if alert.


Hypothermia- Hypothermia occurs when the normal body temperature (98.5 degrees F) drops to less than 95 degrees F. Exposure to cold temperatures causes the body to lose heat faster than it can be produces. Prolonged exposure to cold will eventually use up the body’s stored energy. The result is hypothermia, or abnormally low body temperature. Hypothermia is most likely at very cold temperatures, but can also occur even at cool temperatures (above 40 degrees F) if a person becomes chilled from rain, sweat, or immersion in cold water.

Symptoms of hypothermia include: uncontrollable shivering, loss of coordination, confusion, slurred speech, heart rate/breathing slow, unconsciousness and possibly death. Body temperature that is too low affects the brain, making the victim unable to think clearly or move well. This makes hypothermia particularly dangerous because a person may not know what is happening and won’t be able to do anything about it.


First Aid

  • Call 911 immediately in an emergency.
  • Move the worker to a warm, dry area.
  • Remove any wet clothing and replace with dry clothing. Wrap the entire body (including head and neck) in layers of blankets; and with a vapor barrier (e.g. tarp, garbage bag) but do not cover the face.
  • If medical help is more than 30 minutes away:
    • Give warm sweetened drinks if alert, to help increase the body temperature. Never try to give a drink to an unconscious person.
    • Place warm bottles or hot packs in armpits, sides of chest and groin. Call 911 for additional rewarming instructions.


Wind Chill Chart


Additional Resources

Information for this page was taken from the National Weather Service and OSHA.