CLOUDBURSTS.

Auckland Star, Volume LXIII, Issue 239, 8 October 1932, Page 8

CLOUDBURSTS.

The cloudburst that occurred in the Teliachapi Pass region of California a few days ago, causing the deaths of at least forty people, wrecking a train, sweeping away fifteen bridges and a railway station, and flooding a large area of countryside, was not an unusual phenomenon in that particular part of the United States, even if it was one of the most devastating that has been experienced for several years. Cloudbursts occur chiefly in mountainous districts because the accumulations of water vapour from which they originate readily disintegrate when brought in contact with the. mountain tops. The primary cause is a tornado, one of those cyclical storms which wreak so much havoc in their path. An ascending current of air in the tornado draws the water vapour higher and higher in steady accumulation until one of two things occurs: Either the sheer weight of the mass makes it fall, or else sudden contact with a mountain top precipitates the cloud. The difference between a cloudburst and ordinary rain is that the water from the former does not fall in drops, but literally pours down in a sheet. Travellers in the Rocky Mountains have told tales of almost incredible damage done to the hillside forests by these sudden bursts, and eye-witnesses have spoken of observing from a safe distance what appeared like the contents of a mighty saucepan pouring down on a mountainside to sweep away immense rocks and leave a ibroad, (bare path of e-hingle behind. Once a cloudburst in Montana destroyed 800 head of sheep in one blow. "The cloud," isaid a newspaper account at the time,

"exploded at the head of Dry Run Creek, and came pouring down in a solid wall 32 feet high, carrying off the whole herd." The water that has fallen naturally runs down the mountainsides, and inevitably accumulates in the ravines and valleys, which are the places usually chosen by the settlers for their habitations. Sudden and disastrous floods follow, small creeks become raging torrente, and bridges are carried away. . The calamity that overtook the Southern Pacific train the other day was the effect of such a cause as this. Most of the deep canyons crossed Iby this particular railroad are spanned 'by high trestle bridges. According to one of the cable messages, the train plunged •through a bridge of this type. To give an adequate account of such a disaster would need the pen of a reporter of the calibre of Philip Gibbs, allied to the camera of the producer of one of •those old Western pictures of the silent screen which made such a speciality of "the mighty Limited plunging to its doom amid scenes of incredible confusion." At the 'same time, cloudbursts are not the prerogative of the Roo?*y Mountains, and it is not only in the United SOL tes that terrible railway disasters are caused by storms. In England there have been cloudbursts that have flooded whole towns and destroyed houses of brick and stone. And there was the Tay Bridge disaster of 1879, when as the result of a storm blowing against the iron latticework of the structure, the bridge gave way while a train was crossing it and the seventy-five passengers were drowned. In the States, nevertheless, I things are invariably done on the grand scale. I _ "J. —DONALD J. COWIE.