(WLNS) – If you’ve spent a winter in mid-Michigan you’ve heard the term “wind chill”. We know it means that it’s cold outside but aren’t always clear on what wind chill really is.
Simply put wind chill is a measure of how cold people and animals feel based on heat loss due to wind and evaporation. In cold and windy weather conditions, the skin loses heat through evaporation much more quickly than if the wind were not blowing. Therefore, it feels much cooler when it’s cold outside and the wind is blowing. The faster the wind blows, the greater the evaporation and thus, the greater the chilling affect. This is called wind chill, “real feel”, or apparent temperature.
The wind chill can greatly decrease the time for which frostbite and hypothermia set in. Wet or damp skin means the time decreases before you are in danger. That’s why you should be careful to not overexert yourself when it is very cold outside. The sweat on your skin, your natural cooling system, can accelerate the frostbite or hypothermia risks. But there is no set temperature/time relationship for frostbite because there are factors that can impact the onset.
But in order for one to suffer from frostbite, the temperature must be below 32°F (freezing). That’s because frostbite is what happens when skin freezes, and eventually dies. Strangely, if the temperature is above freezing but the wind chill is below freezing, frostbite can occur. As a general rule, the below values can be followed:
Wind chill of -20°F means frostbite in 30 minutes.
Wind chill of -35°F means frostbite in 10 minutes.
Wind chill of -55°F means frostbite in 5 minutes.
One thing to always remember: Do not rub snow on frostbite. In fact, do not rub the damaged tissue at all. Instead warm the frostbitten area gradually with body heat (like holding your fingers under your arm) or placing the area in comfortably warm, but not hot, water.