Sunday, January 27, 1952.
ASK THE WEATHERMAN
(CBC Trams-Canada Network)
LOOSE USE OF WEATHER WORDS
P. P. Saltzman,
Dominion Public Weather Service, Toronto.
The weatherman, as we all know, is one of the cartoonist's favorite targets, As often as not, when he runs out of ideas, he lampoons the weather forecaster. And as the song says, the first year is the worst year and after that we get used to it. But there's one thing your weatherman will never get used to, and that is being criticized when he's right. For--and this may be contrary to prevailing opinion--your forecaster is more often right than wrong. The trouble is. though that this is not always realized. And the reason is- sometimes the terms your weatherman uses are not understood as he meant them to be. The people who hear the weather words may not get the meaning out of them that the forecaster put into them. This matter of the right use of weather words is one of the problems facing your forecaster in putting his ideas across as clearly as possible. Many weather words mean different things to different people, and mean different things to the same people at different times.
Such words as fog arid haze, sleet and drizzle, blizzard and cyclone, are more often used loosely than wisely. People are often uncertain just which is the right term and so are a bit vague and inconsistent in using these weather words. This may do no great harm over the teacups but it does make it hard to put forecasts across with precision, for if a word starts muddled it'll end fuddled. As an example, most people mix up fog and haze. Some think these are one and the same. Others believe that fog is merely thick haze. To your weatherman though there's a world of difference between the two. Fog is wet, haze is dry. Fog is nearly always pure white, haze is generally blue or blue gray. Fog is a cloud of water droplets hugging the ground, is usually no deeper than a few hundred feet, and forms when the air is cooled and disappears when the sun evaporates it. By contrast, haze is made of dust, sand, smoke, and salt., usually extends to 10000 feet, and is not burned off by the sun but hangs around until washed out by rain or blown away by the winds of a fresh air mass. So you see there is a very real difference between fog and haze.
Incidentally, there is no essential difference between fog and cloud. Both are made up of water droplets or ice crystals. Thus fog might be called cloud on the ground and cloud might be called fog in the air. In California, this is actually done, and low cloud is called high fog. I suppose in Florida they do the opposite. There perhaps fog is called a low-down, no-account cloud.
Many people assume that cloudy and overcast mean the same thing. But that is not the way your weatherman intends them. To him overcast means a sky completely covered with cloud and cloud moreover,. which is thick enough to blot out the sun. On ~he other hand, he will use the word cloudy when he means a sky which is anywhere from 50- 99% covered with cloud. With a forecast of cloudy, therefore, you can expect occasional or even plenty of sunshine, but with overcast, no sun at all. The weatherman may issue a forecast saying "cloudy with a few sunny intervals," or "clear with a few cloudy intervals." He has in mind one of those days when the clouds come and go, sometimes nearly filling the skies, sometimes with only scattered humps of cloud high on the horizon. But when he says overcast, he means a darkly clouded--overcast sky--just like the word really sounds. Cloudy is more of a fair weather word--overcast with its sombre sort of meaning--more in keeping with a rainy weekend. This is not to say that a forecast of overcast always implies bad weather. We have all seen those dull dreary days when the sky is completely covered and yet no rain or snow falls. Even more common are the cloudy skies that remain quite dry. Thus it would be quite wrong to assume that just because your forecast says overcast that bad weather is expected. This is even more true when the forecast says cloudy. All of which means that it pays to read the complete forecast and not just the one-line summary that you so often see at the top of page one of your favorite newspaper.
Another brace of weather words often loosely used are: blizzard and snowstorm. Too often blizzard is used to describe simply a heavy snowfall, or even a. series of sharp snowflurries. Well do I remember the heavy Toronto snowstorm of a few years back when 20 inches of snow paralyzed the city, and all our headlines shrieked: Blizzard hits Toronto. Nothing of the sort. These heavy snowfalls in Eastern Canada that we brag about as blizzards are not worthy of being called even blizzettes. The truth is that to most people on the prairies and to your official forecaster, a blizzard is a cold driving wind filled with blinding snow. There doesn't even have to be any new snow falling at all. The old dry powdery snow lying on the ground may be picked up by the stormy winds and swirled around in a blinding fury. So, in order to stick to the correct use of blizzard your weather service has set down certain rules for judging a storm and deciding if the name blizzard fits. Here are the rules: The winds must reach or exceed at least 25 miles per hour. The temperature must be expected to fall below a certain chilling figure -- for example, on the prairies this figure might be 10 below zero F. The visibility in the blinding snowswirls must be cut down :to one-half mile or less. And all of this must last for at least six hours before your forecaster can call it a blizzard. Now even allowing for a certain degree of loose use, it would be hard to apply this strict definition to the type of Eastern Canadian snowstorm that merely leaves a heavy blanket of fresh snow after it passes. Yes, blizzard is a fine word, one of the few contributed by Canada to the world's dictionary of weather words, and its meaning should not be diluted.
So I fervently hope we will see less and less of this loose use of weather words so that the forecaster and his public may understand each other a bit better.