January 26, 2008 in HandleX

Relief from cold snap should be here soon

Michelle Boss Correspondent
 

This past week we saw some of the coldest temperatures of the season. Officially, overnight lows in the Coeur d’Alene area dipped into the single digits and even down to minus 2 degrees at the airport. Many rural locations, however, saw temperatures much colder than that.

A snow-covered ground, followed by strong high pressure with clear skies and light winds, will usually result in the chilliest temperatures. Unfortunately, for those whose work schedule requires an early morning commute, the temperatures seem to bottom out right before sunrise, which occurs these days around 7:30 a.m. That would be just about the time many folks have to venture out of their cozy households, into their frigid cars.

Coeur d’Alene’s coldest average temperatures usually occur from Dec. 26 through Jan. 8. We’re likely hitting rock-bottom right now in the temperature department, so if you’re tired of being in the deep freeze, there should be some relief right around the corner. We’re already enjoying nearly a full hour more of daylight than what we had at the winter solstice. In the days before Christmas, we were only getting 8 hours and 33 minutes of daylight. We are currently up to 9 hours and 16 minutes and gaining 2 to 4 minutes each day.

Though actual air temperatures may be on the rise now, one factor that can definitely kick the frigid factor up a notch is the wind. The Coeur d’Alene area and points westward toward Liberty Lake, are notorious for their strong northeasterly winds. Winds from that direction are enhanced by a funneling effect due to the surrounding terrain. The effect is lost by the time you get into Spokane. Though I’ve seen the pattern time and time again, I have to admit I often forget to mention this factor in my weathercasts when northeast winds are forecast for the area. It may seem like a small detail to overlook, but when Spokane has northeast winds at 5 to 10 mph, while Coeur d’Alene’s winds are 15 to 30 mph, the difference in wind chill can be more than 10 degrees.

Wind chill is a term which still confuses many people. Though it is given in degrees, it is not an actual temperature. An air temperature of 20 degrees will register the same on a thermometer whether the wind is calm or howling at 30 mph. What the wind-chill number indicates is how the wind affects a human body’s sensation of temperature.

Wind accelerates the heat loss from our bodies, making us feel colder. The reading does not apply to pets, or to any inanimate object. Wind-chill readings below freezing, when the air temperature is not, will not cause water to freeze. Wind chills can become hazardous if you are not properly dressed (any skin exposed), and the readings dip to minus 20 degrees or colder. That is when exposed body parts can be affected by frostbite in less than 15 minutes. At an air temperature of 10 degrees, you would need a ferocious wind of over 55 mph to reach this threshold. At 0 degrees a wind of only 15 mph brings the wind chill to minus 19. The National Weather Service will issue a wind chill warning when wind chills are forecast to be at minus 20 or colder.

It is interesting that the formula used to calculate the wind chill index was changed in 2001 as a result of advances in science and technology, and the desire to standardize the index of temperature extremes internationally. If you are curious, you can visit www.novalynx.com/ reference-wind-chill.html to see the drastic differences between the old calculations and the new.


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