Winter arrived with a gentle introduction in most parts of the Prairies this year. Now it’s time for the chorus: Is it cold enough for ya?
If it’s cold enough to ask, the answer is invariably yes. But how cold is it?
So cold that you need jumper cables to get the driver going, as well as the truck? So cold that lawyers put their hands in their own pockets?
Well, there are more scientific measures, Environment Canada assures us. Among them is a new program for reporting wind chill. The change was announced in October, but happily wind chill reportage hasn’t been much of a factor until now.
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The old method of wind chill reporting was based on the cooling rate in watts per square metre. Some people had trouble wrapping their mittens around that concept, so the new measurement will be reported in “a temperature-like unitless index,” says Environment Canada.
For example, you might now hear on the radio that “It’s Ð10C, with a wind chill of Ð20.” Wind chill is a feeling of cold rather than a real temperature, so wind chill figures will be given without mention of degrees.
New measures were derived through rigorous testing based on the cooling of the human face, the part most likely to be exposed to winter weather. The weather people tested the scale on willing human subjects, who were fitted with temperature probes in various bodily orifices and asked to walk on treadmills in a refrigerated wind tunnel.
Sounds like that regular winter morning trip to break the ice in the water trough, doesn’t it? But without the probes, of course.
New wind chill measures are also calculated at a height 1.5 metres above the ground – about the spot where your face would be – rather than 10 metres above the ground like the old measure.
All in all, this new wind chill measure seems to make a lot more sense.
A few more words about weather, while we’re on the subject. The WP weather statistics, on the inside back page of every issue, has snow and rain totals listed as precipitation. Environment Canada reports it this way for better accuracy.
Weather stations melt the snow and report a liquid measurement. Wet snow will measure higher than dryer, powdery snow, though a ruler might tell you the snowfall amount is the same. As a general guide, on average one centimetre of snow yields about one millimetre of precipitation.
