background tile:
| The Blue Norther | "...a winter wind that precedes a fast moving cold front, replacing warm, moist air with a furious, bone-chilling northerly wind that can drop temeratures as much as 50 degrees Fahrenheit in two or three hours." |
| Chinook | "...are warm, strong, westerly winds appearing out of clear skies
several times each winter in the eastern foothills of the Rockies from
Colorado to Alberta, Canada. they often raise the temerature overnight
by as much as 40 or 50 degrees. By the time Chinook winds reach the
high plains, they have lost so much moisture in their passage over the
Rockies that humidity is only about 40 percent or less. That dry,
relatively warm air can evaporate snow at the rate of an inch per hour--a
phenomena that caused the Blackfoot Indians to call the wind "snow eater"."
On January 22, 1943, Chinook swept in to Rapid City, South Dakota and raised the temperature from -10 to +45 degrees Fahrenheit in approximately two minutes. |
| Santa Ana | a hot, dry wind that sweeps through southern California, sometimes creating massive, blinding dust storms. |
| Alberta Clipper | Not a wind per se. An Alberta Clipper is an area of low pressure that forms over Alberta, east of the Rocky Mountains. Once formed, the Alberta Clipper moves rapidly to the southeast, reinforcing cold temperatures and bringing light precipitaion, most often in the form of snow. |
| Nor'easter | An intense low pressure system that tracks along the east coast of the United States, usually during the fall, winter, and spring months. These storms can produce strong northeast winds, large waves, and intense precipitation. |
| In America, and most other areas of the world, a west wind is the most common and benign wind. East winds are caused by counter clockwise rotation in low pressure fronts which often precede stormy weather. |
|
|
|
|
| calm | 0-1 | smoke rises vertically |
| light air | 1-3 | smoke drifts, ripple patches on water |
| light breeze | 4-7 | leaves rustle, consistant water ripples |
| gentle breeze | 8-12 | leaves and twigs move, small waves |
| moderate breeze | 13-18 | small branches move, longer waves |
| fresh breeze | 19-24 | small trees sway, a few white caps |
| strong breeze | 25-31 | large branches sway, overal white caps |
| moderate gale | 32-38 | larger trees sway, white caps and swells |
| fresh gale | 39-46 | twigs break off trees, longer and higher waves |
| strong gale | 47-54 | branches break off trees, tops blow off waves |
| whole gale | 55-63 | trees uprooted, churning sea |
| storm | 64-73 | widescale damage |
| hurricane | 74-136 | devastation |
| In my home state
of Minnesota, windchill is a common topic of conversation for at least
nine months out of each year. Denizens of cold weather regions ignore
this phenomena at great risk. High winds, even on a relatively balmy
winter's day can be fatal. Deaths related to windchill are not as
frequent, or as feared, as they once were. The most likely explaination
for this improvement is the availability of shelter to most individuals
caught out in windy conditions. Imagine, though, how terrifying it
once was . . . when the shelter of the nearest building was frequently
an hour or more away.
Cold air blown by wind increases heat loss
at a much faster rate than cold alone. To determine the windchill
factor, and to understand it's impact, multiply the wind speed by 1.5 and
subtract it from the temperature of the air. The resulting temperature
reflects the damage that the correct conditions can inflict on human or
animal.
|