SAMOAN HURRICANE.

Otago Daily Times, Issue 19688, 15 January 1926, Page 10

SAMOAN HURRICANE.

ISLAND SCIENTIST’S YIET7. THEORIES AS 'TO CAUSES. COMBINATION OF CONDITIONS. The director of the Apia Observatory, Mr Andrew Thompson, wbo is at present in New Zealand, stated last week that the worst previous cyclone recorded in Samoa was in 1850, when the barometric pressure fell to the lo.vest point recorded in the Southern Hemisphere, 27.1 in. According to all accounts the Island of Upolu was destroyed as if by fire. The population then was bigger than it is now, and a great deal of suffering resulted. Curiously enough, the adjacent island of Savaii escaped damage. Another severe cyclone occurred in 1916, but then Apia escaped and the neighbouring islands suffered. Mr Thompson has been engaged in studying the 1889 disturbance. Many people considered that the cause of the trouble was a tidal wave, but ho was assured by an eye-witness that a cyclone was the cause. The wind, it was estimated, travelled on that occasion at a speed of 85 miles an hour and blew all the gear off the vessels. That rate of wind has never been equalled since that time. But according to telegrams received concerning this month’s disaster, the waves had been greater than they were in 1889. Mr Thompson considers that in the present case the danger lies in the falling of trees on the native houses. Continuing, he said he considered that an explanation of the phenomena lies in a combination of two theories. Where there is very hot weather and a vast stretch of water, a tremendous quantity of water is suspended in the atmosphere in the form of steam. If by some accident the great body of steam is raised slightly higher in the atmosphere it will strike a cooler stratum and he converted back into water. The water takes np only 1-1800th part of the area of steam,and when this shrinkage takes place over a. large space an enormous vacuum is left, which Nature seeks to fill as rapidly as possible. The surrounding air will be rushed in at terrific force to fill the vacuum, with a spiral motion. The wind will rush round and round, gradually drawing nearer to the centre. This inrnshing of the wind will continue until all the vapour is condensed hack into water. But the centre does not remain stationary. The earth moves from west to east, hut the cyclone centre lags behind, and gradually moves into the higher latitudes, that is, it travels north or south of the equator. Samoa stands directly in the path of some of these storms when they move south of the equator, and so receives the effect of their enormous force. In higher latitudes still, their energy becomes expended, so that places in the south of Samoa are not so violently affected. Tlie cyclone track is sometimes quite narrow, which explains why one island may receive its force while a neighbour may remain unharmed.

This theory does not account for the fact that places to the east, Say, from Tahiti to the west coast of South America, do not get cyclones. The other theory disposes of this suggestion. North of Samoa two air currents meet, and this, it ,is supposed, starts the air whirling in a circular motion. Between Tahiti and America no strong air currents meet, and therefore no cyclone is caused. But, were this second explanation the only one, it would not explain the terrific force of the cyclones, because the junction of two air currents would not, in itself, cause the tremendous acceleration which actually takes place The advocates of the two theories will allow no compromise, but Mr Thompson believes that both are factors in a cyclone.