TORNADOES IN AMERICA

Otago Daily Times, Issue 19964, 4 December 1926, Page 26

TORNADOES IN AMERICA

WHAT THEY ARE AND DO. Written for the Otago Daily Times. By Sioux. It was only a few weeks ago that the attention of the world was arrested by the news of a devastating tornado in the State of Florida, America, as the result of which hundreds of lives were lost and many million dollars’ worth of property was destroyed. Since then the cables have conveyed to us an account of tornadoes which swept sections of Louisiana, Arkansas, and Missouri on November 26, leaving a trail of death and destruction. With the severity of these terrific storms the reports of the newspapers have made us familiar, but few of us are aware of their frequency and regularity in some parts of the United States. During the past eight years, statists js show, there were over 800 tornadoes in the States. America has not a mono poly of tornadoes, but it has far more than any other country. Other lands have their hurricanes and typhoons and various big winds, but few tornadoes, and tornadoes are the greatest winds that blow. The States of America do not all share equally in the visitation of tornadoes. The tornado area comprises the 20 States which are known as the Middle West. It will be seen that the places which have recently experienced tornadoes are within the area defined. According to Mr Charles Talman, of the United States Weather Bureau, nearly 90 pei- cent, of the tornadoes which occur take place in the Middle West. What is a tornado; what causes it? What are its habits? Students of this tiger of the air say that the tornado comes from the south-west, and travels to the north-east. The tornado is the effect of the meeting of tremendous opposing air currents, from north and south. The southern currents are warm, humid, and of low pressure; the northern are cool, less humid, and of high pressure. A mighty battle between these air currents results in violent vertical movements. Masses of air are “overturned,” rushing upward and downward. The cold air striking the warm, moist air produces huge clouds. These ominous clouds of inky black or livid green aiM seen opposite to each other in the south west and in the north-east. They seem to boil up, rising to an immense height. The opposing clouds then approach one another, and, as they do so, are thrown into great confusion, breaking up into small portions, which dash pell moll over one another, now darting towards the earth n °w rushing upwards like sky-rockets. Closely following upon this condition the funnel-shaped tornado cloud generally appears in the western sky, moving boldly to the front from the confused mass of flying clouds. This tornado cloud sounds its approach with a mighty roar, not dissimilar from that made by a train crossing a steel £?•' T* lo tornado cloud is really a whirling vortex of a ir, with a hole—a partial vacuum—in the centre. It forms high above the earth’s surface. As its whirlin'' motion grows more violent, it reaches lower and lower, until its writhing tip touches the ground. Then it proceeds on its relentless cross-country march, and trouble for those in its path begins. It may be thought that the advance speed of a tornado is very rapid This is not so, however. Its progress across the country is at the rate of only 25 to 50 miles an hour. Ihe terrific power of the tornado is due to its motion within itself,—to the velocity with which the air whirls around the centre of the vortex. This velocity cannot be measured by any instrument,' but, judged by the force which it exerts, it is estimated at about 500 miles an hour. The fury of a hurricane, it may be remarked, is less concentrated, and its velocity reaches only about 100 miles an hour. Experts declare that the force or pressure of a 500mile wind is 25 times as great as a 100mile wind. The awfulness of a tornado can therefore bo imagined. The tornado usually develops between three and five in an afternoon, and if it happens to travel for several hours it may reach a district at night, a s was the case at Missouri last week. Another characteristic of the tornado is that, on occasions, it proceeds by leaps and bounds, as it were. The tip of the tornado funnel temporarily fails to reach the ground, and whenever this happens no havoc will bo wrought. Then it will descend again, only far enough to rip the shingles from a roof, or even the top rail from a fence. Then it may rise once more, and miss another stretch of its path. In the report of the latest tornado, it was mentioned that it swept a narrow pathway through Louisiana. Its narrow track is another characteristic of the tornado. It is a stprm of terrific intensity, but it is also the smallest of the great storms. At times the track of the tornado may bo only a few yards,, or even a few feet, in width. The average width is about a quarter of a mile. T/ie length of the track is usually short aho. Sometimes it is loss than a mile long. In rare cases the track has extended to a length of two hundred miles. As to the devastation wrought by these terrific storms, the recent happenings furnish arresting evidence. Tornadoes do some dreadful things; they also do some things that are queer and freakish. A farmer who suffered by a tornado some years ago has recounted some of the incidents connected with it. Ho states that, although his house was completely destroyed, the barn near by was left intact. Several occupants of the house were carried about 200 yards, first in one direction, then in the other. They were covered with mud, their clothes wore torn to shreds, and fragments of debris were driven into their flesh. A sewing machine was broken into 40 or 50 pieces, but a carpet, which hao been tacked to the floor, was carried some distance, and not torn, A largo iron-bound trunk was torn to pieces, and the lock was afterwards found, half a mile away, driven into a fence rail. Several chickens were carried a mile, and literally stripped ot their feathers. Debris from the house was scattered over a region several miles long and a mile wide. The same tornado performed many other feats. It moved an iron bridge, weighing 216 tons, twisting the metal rods and beams into a confused mass. Passing up a river it forced the water out, so that the bed of the river was uncovered. At another point a house was lifted, carried over some trees, and then dashed to pieces on the ground beyond. A buggy, weighing 3001 b, was carried into a tree, and left 64 feet from the ground. A chicken coop, weigh ing 751 b was carried four miles, and a basket of books, weighing 501 b, was carried two miles and a-half, and found hanging in a tree. Sheep were found shorn of their wool. Some potted geraniums were carried a mile, and were not at all injured. Mr Stuart Mackenzie, writing about tornadoes, says that photographs have been taken of straws that have been driven endwise into planks or posts by these fearsome winds. One man. who sought refuge in a stack from an on-coming tornado, found himself in the position of the man in the Scripture, who built his house upon sand. The tornado dispersed the stack in a twinkling, and the unfortunate individual was lifted up and carried onward. As to the frequency of tornadoes, February, 1884, holds the record for America. In one day, from 10 in the morning until 12 at night, there were no fewer than 50 tornadoes. Eight hundred persons were killed on that disastrous day. The idea that when once a place has been visited it is thereafter free from visitations does not hold good. One small town in Western Kansas was struck by a tornado there years in succession on the very same clay of the same month, and almost on the cciy same hour of the day. , , , Lieutenant Finlay, who wrote a book on tornadoes 40 years ago, urged people living in districts likely to bo visited, to construct tornado cellars, and his advice has been largely followed. Some people had the idea that when the great prairies he- | came cultivated the frequency of tornadoes would be reduced. Scientists ha,ve dis-| proved this, and say that America will) continue to have its visitations. As the area visited by tornadoes is comparatively small, however, millions ot persons in the States will never have the experience ot seeing one, j