tree limbs encased in ice from an ice storm on 16 Dec.
Consult the Windchill Chart below to avoid severe cold—and frostbite.
Also, see the tips below on windchill hazards and what to do.
Click to expand Canadian Windchill Chart (PDF).
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- If windchill is below -10° C, there is low risk of frostbite but there is risk of hypothermia if outside for long times without adequate protection. Wear insulated layers and footwear with a wind-resistant outer layer and waterproof footwear. Stay dry and active.
- Below -28° C, there is added risk of frostbite. Exposed skin can freeze in 10 to 30 minutes. Check face and extremities for numbness or whiteness. Cover all exposed skin on top of the precautions listed above.
- Below -40° C, high risk of frostbite means exposed skin can freeze in 5 to 10 minutes (and faster in winds over 50 km/h). All skin MUST be covered. See precautions above.
- Below -48° C, very high risk of frostbite means exposed skin can freeze in 2 to 5 minutes (and faster in winds over 50 km/h). Cut short or cancel outdoor activities.
- Below -55° C, extremely high risk means skin will freeze in less than 2 minutes (and faster in winds over 50 km/h). Very dangerous. Outdoor conditions are hazardous. Stay indoors.
Catherine Boeckmann
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I understand that windchill describes how fast the body or skin looses its heat from rapid air flow, the wind. But I've always wondered, do inanimate objects get colder with a greater winchill factor.?? Specifically water pipes. Will they freeze if the ambient temperature is above 32 F even if the winchill factor is say, 10 F to a human.??
No, it will not freeze because the speed of wind does not affect air temperature but it will remove heat from objects faster. This means that the temperature of the water in the pipe will drop to the temperature of the air if the wind speed is fast enough. Buildings, your house, will also lose heat faster with wind; your house will need more heating because the exterior walls get colder when the wind is stronger. Like the pipe, if the wind is strong enough, and you do not heat the house, the temperature of the house will eventually reach the temperature of the blowing air. The worse the insulation of walls, windows and doors the faster the heat loss and temperature drop will occur.
"wind-heat" will occur is the outside air is hotter than the pipe, the house or your body but the temperature of the pipe, the house or your body will not go higher thant the temperure of the air. You could die if the air temperature is so hot that you lose water and you can also overheat if you can not get rid of the heat the body always generates to stay alive. I do not know why the body can not drop the amount of heat it produces as the air temperature approaches the normal body temperature of 36-37 degrees C. I suspect it is because the interal organs produce heat as they function and that heat must be removed to keep the 36-37 degree temperature organs need to function properly, but as the air temperature increases the heat loss through the skin to the outside air is not quick enough. This is why, first the body starst to perspire because perspiration helps removal of body heat becaure as sweat evaporates it drops its temperare of the sweat that is about to evaporate. But it can reach a point where even persiration is not enough if air temperature is hot enough. I suppose it is a bit like a car engine; it works best at a certain temperature; if the air temperature is low more of the heat the engine produces (engines always produce excess heat) is removed by the coolant circulating through the radiator. As the temperature of the air rises the coolant circulating through the radiator keeps removing heat. Engines produce huge quantities of heat always, that is why even in very cold weather the radiator and the engine are hot. But, as you might have noticed, it is in hot weather that engines can overheat if, for example, there is a loss of coolant or the fan belt breaks and lees air cools the radiator.
The wind chill or whind heat happens to all objects that are at a different temperature than the blowing air. I believe, the humidex index sort of takes care of the problem in hot weather, but includes the relative hpmidity of the air because the humidity in the air affects the evaporation of sweat from the skin and lessens the ability of the skin to cool the body. Of course, as you sweat, in any weather, you have to replace that water because organs need water to function and you need more water to continue the evaporation process to increase the cooling.
I am sure there are many other interesting facts about wind temperature and pipes, houses and the bodies humans and other living things. Reptiles have a different system, that is why in cold weather the slow down as their body temperature drops.
