BIG WIND BLOWING

Auckland Star, Volume LXIX, Issue 280, 26 November 1938, Page 12 (Supplement)

BIG WIND BLOWING

BY a freak of Nature there was a low-pressure instead of the normal high-pressure area in the North Atlantic on September 2 1. So a big wind that started to whirl over some little volcanic islands off the sultry West African coast hit the seaboard of the American Continent at Long Island instead of Florida, and it was in the nor,th instead of the south that hundreds were killed, thousands injured, and millions of pounds' worth of property destroyed as by a blast of high explosive.

ByA. Gaston

-—Copyright

Otherwise there was nothing exceptional about the great hurricane that competed with the European crisis for headlines and news story space on September 22.

In the West Indies weather station, where I have been observing wind phenomena for the past six years, they get out the hurricane-warning flags in early August. As soon an the black-squared red flags are hoisted, the hurricane boards go up on whop and house windows; cattle and sheep are chased into the storm barns; fishermen beach their boats. It's bad enough if you're ready for it, but if you're not, disastrous things can happen—as they did when the great tidal wave hit Long Island, smashed 700 Ashing boats, and wiped out summer bungalows and other residences along the beaches.

In any ease, the "big wind" regularly takes its toll. Native villages in Haiti, Dominica and the islands—these usually bear the brunt of the blow. Seven "hi;; wind*"' a year is the average. Every one is a killer and destroyer.

A noted meteorologist takes you backttage of Nature's greatest drama—the hurricane. Last September a big one ran out of its usual path, hit Long Island and New York, kdled 350 people and injured 8000 and did £30,000,000 worth of damage along America's north-eastern seaboard.

Weather j<i«striiment« do not i»tand up to eiirh pressure; if they di<l, their fixings would not. Calculations based on totmrtiircs blown down or shifted rea<'h a« hiffh a* ISH-2HO mi!.** an hour. I'nder that telephone poles and trees are uprooted and to>*ed about like paper darts, stone walls are blown down and

■wooden Ktrueture* torn apart, l>i;r boats are carried inland oil tidal waves, an<l the t.ea is Mown up t-o hijxh that it will sweep rijrht over an Wand, or inundate a sea-coast city. Few folk in the hurricane zone are taken by »-urpri*e by a , ~big' wind." It plenty of warninfr. The biggest one in liiv zone laet year heralded its

coming by a strange, ominous quiet. I became aware that the birds had ceased to sing. They do not need to observe the sky, and note the presence of cirrus clouds, and the quickening of their pace, to know that a "big wind" is on its way. Even the ants know-—you will see them stop work and hurry back to their nests like battalions of soldiers scurrying to cover before a bombardment starts. One has a sense of oppression. That is a physiological phenomenon. It becomes close; no air movement. Yet the tide is abnormally high. Then the sky darkens, one hear« the distant rumble of thunder, a gust of wind suddenly breaks the stillness; and. with appalling swiftness the storm breaks in torrential rain and roaring thunder and a fury of lightning. Then the "big wind'' arrives like a thousand howling shells. Amazing Vagaries I have known a hurricane blow for 70 minutes and for (50 hours. The pace of the storm is seldom more than 13 miles an hour, although inside the storm zone the big wind is blowing at velocities from 15 to 200 miles. And this storm will move leisurely over thousands of miles of sea and land. The great hurricane of September, 1300, blew almost the whole month—its passage from the time it entered the Gulf of Mexico to the time it reached the St. Lawrence, was charted. The chart record in all covers 21 days. In that time it killed 2500 jveople.

It ie fortunate that, a tornado is not a. traveller, like the hurricane. Tornadoes are whirling storms. like hurricanes. Rut. the rate of whirl is hi«her--*n high that the whirling column will create a partial vacuum around a house in its path, causing the air inside the structure to I»]ow the walk out. In 192.5 a tornado in the Mississippi Valley killed 700 people. If it had travelled as far as the average hurricane it would have killed 7000 or 70.000. For it moves too fast, for warning, and while meteorologists can chart the path of the hurricane as it comes—hurricane warnings come first from ships at sea. reporting to Government stations, and the probable course can be worked out—they have to be content to chart the path of the tornado after it has passed on its deathdealing way. The path of a tornado is seldom more than 40 to 00 miles long. The tornado is narrow, too—at sea, it is as narrow as the water spout it creates. A hurricane can be 800 to 1000 miles across. They start ill equatorial calm when an air mas* gets overhot and overladen with moisture in an atmosphere at once sultry and wet. The mass rises as its heat increases, and as it rises it expands and cools. The moisti.re condenses and falls in rain. A powerful current of air is drawn up in ihe wake of the rising mass and a wind is generated. This wind imparts a rotary movement to the vertical column. The column begins to whirl, momentum increases; and the hurricane starts out on its travels, storming along the path opened by the air inflow of low-pressure areas, and being '"herded" as it goes by high-pressuro areas, where there is an outflow of air. The "Herding" Process Foitunatelv for America and Europe and for the shipping which plvs between the two continents, high-pressure areas predominate in the North Atlantic and low-pressure areas predominate in the South Atlantic, so that the path of the hurricane from Nature's factory in the vicinity of Cape Verde group of volcanic islands—the windless Doldrums—is usually across the South Atlantic, and it. normally strikes somewhere along the Florida coast, is bum|>ed off out to sea again by the high-pressure air over the land, and poes on storming north to Newfoundland, where the high-pressure air barriers again thrust it off. herding it east until it reaches Iceland, and blows itself out in cold air.