TOLL OF THE TORNADO

Sun (Auckland), Volume IV, Issue 1046, 9 August 1930, Page 28

TOLL OF THE TORNADO

HUNDREDS KILLED EACH YEAR COMMON IN UNITED STATES Tornadoes, tho world’s shortest and most vicious storms, occurring almost exclusively in the United States and in Australia, kill in America every year an average of 310 people by about 130 swift strokes from the heavens. Although tornadoes occur practically every month of the year (says Science Service’s “Daily Science News Bulletin”), most, of them strike during March, April, May, and June. In 1929 there were 17 tornadoes in March, killing 20 people; 60 in April, killing 168; 37 in May, killing 35; and 11 ia June, killing 2. During the first four months of 1930 only about 20 people had been killed by the storms, but to these must be added more than 100 lives lost in two outbreaks of tornadoes the first part of May. We read further: —

“Tornadoes of America are confined almost entirely to the Mid-West, where the most destructive one to visit this country swept through Missouri, Illinois and Indiana in March, 1925, killing 695 people, injuring 2,027, and destroying 16,500,000 dollars’ worth of property. “St. Louis has suffered more from tornadoes than any other American city because that city happens to bo the biggest target in their territory, and they naturally hit it often. In May, 1596, one of these ‘twisters’ killed 255 people in the city; and again, in September, 1927, S 5

people were killed, 1,300 injured, and 15,000,000 dollars’ worth of damage was done. “In spite of the great havoc wrought the tornadoe’s career is brief. The entire storm seldom lasts longer than an hour, and not more than a minute in any one place. It usually cuts a path about 30 miles long and orily 1.000 feet wide, so narrow that, the United States Weather Bureau advises that if underground shelters are not available one should try to run out of the path of the approaching storm.” Concerning the make-up of a tornado for its run of destruction we are told: — “The tornado itself is a whirling vortex or funnel of winds reaching high up into the sky. It travels from 25 to 40 miles an hour. The velocity of its whirling winds has never been measured, but, judging by tho destruction they do, meteorologists say their speed must reach 400 and 500 miles an hour. In the storm’s centre a slight vacuum is created, which is largely responsible for the many miraculous feats credited to tornadoes. When this area of low press-ure surrounds a house it literally causes the structure to explode, because of the higher normal atmospheric pressure remaining in the house which must have immediate outlet.

“Meteorologists have not yet satisfactorily explained the conditions existing between the Rocky and Appalachian mountains, which are best suited for the birth of tornadoes. They believe that currents of air blowing in opposite directions at the cloud level set up the Initial whirl, which at certain times will extend to the ground and form a tornado.

“This is most likely to happen in the south-eastern portion of a low-pressure area that is especially well developed iu a north and south direction. The tornado will also be encouraged by a high-pressure area following close behind the low as it moves across the country from west to east. The cool air of the high tends to replace the warm air of the low, and the warm air near the ground is driven up through the whirl with an enormous display of energy. “These conditions sometimes occur over an area as large as several States and produce a dozen or more tornadoes in a very few hours. An unusually destructive grouping is found in the Weather Bureau records for 1924, each group coming at the end of a consecutive month. In March there were 12 tornadoes within 22 hours; April, 22 within 36 hours; May, 11 within 17 hpurs; and June, 4 within 3 hours. Each killed scores of people and destroyed millions of dollars’ worth of property. The storms dip to the earth and often jump «long their path, as is shown by the fact that large areas in the path may be left entirely unharmed. “Over the water a tornado becomes a waterspout, and as a waterspout moves over land it becomes a tornado, if it is sufficiently strong. The vortex of whirling winds, which sucks up water from the ocean, and anything that can be loosed from the land, is usually only a few score feet in diameter.” Of tornado “chances” we are informed that — “In spite of the fact that tornadoes are so damaging when' they strike, even in the most threatened area, houses stand much less danger of being injured by, tornadoes than from being hit by lightning or burned. But the chances for greater total destruction are increasing as the population increases. ,simply because of the greater opportunity the storms will have of hitting people and houses. “Nine per cent, of tornado damage is done in lowa. Missouri suffers next, and Kansas, Tennessee, Alabama, Minnesota, Illinois and Wisconsin follow in order. Eighty per cent, of the storms occur between noon and 6 p.m.”