# Typhoon of August 5th to 23rd, 1924/Preliminary Remarks

THE TYPHOON OF AUGUST
5$^{TH}$ To 23$^{RD}$ 1924.
I — PRELIMINARY REMARKS.
We publish the extraordinary path of that protracted cyclone, not so much on account of its novel and quite abnormal character, but also in view of the many valuable details it may offer to navigators, We are generally wont to divide the paths of typhoons into three principal classes, leaving aside their minor and secondary motions.
The first kind is composed of those which follow a straight course. Starting from the Caroline Is. the south of the Marianas, or formed on the Pacific, to the offing of the Eastern Philippines, they advance towards the W or the WNW, going very seldom beyond the 20" degree of latitude, and in the end striking the coast, between Cochinchina and Kwangtung. These typhoons occur frequently in the beginning or at the end of the season, before the middle of July or after the first ten days of October.
The second group comprises the typhoons, which coming approximately from the same places, appear chiefly in the middle of the hot season, and attracted by the area of low pressures that prolonge to the N and the NE the deep minimum of India, follow a NW course. towards the Continent, and enter China at any place between Kwangtung and Shantung, to fill up on land. Frequently they deluge our countries with a heavy rainfall, and cause considerable damage throughout whole provinces by the floods with which their passage is attended, raising even at times destructive tidal waves at the mouths of the rivers.
Lastly the third class, the more numerous, is formed by the cyclones, which follow a path that has been named parabolic. The storms of that kind advance generally towards the WNW or the NW at the commencement; starting from their original birth-place they then continue in that direction, until they reach some degrees above the Equator, in latitudes comprised between the 20th and the 30th parallels. There they begin to trace the apex of a curve, roughly parabolic, by veering gradually to the N and the NE, the convexity ot the track being turned to the west. They then move towards the NE, accelerating their speed, when they arrive at the regions where the upper currents of the atmosphere are flowing intensely ​in an easterly direction. Often they pay visits to the Empire of Japan, and are even felt, across the Pacific; where some of them have been followed, step by step, as far as the western coast of North America, and even on that continent.
As a rule, and in the far greater number of cases, the tracks of all these cyclones are fairly simple. To the principal movement of translation, however, may be added some wanderings or swervings to the right. or to the left, similar to the winding of an eddy produced by the stream of a river. But these accidental motions, very difficult to trace with certainty in so vast a whirl as a typhoon, are relatively very limited and of short duration, and they do not affect the general pace of the trajectory. This time the matter is one of a well constituted storm, with a deep and well defined central vortex, surrounded by violent winds, which for more than ten days moved along an apparently capricious path, recurving twice to the same place, between lat. 25° and 30°, always in close vicinity to the chain of islands joining Formosa to Japan, Thanks to the observations of the meteorological stations established on these islands, together with the reports of the steamers affected by the cyclone, the successive positions of the vortex may be determined with a fair degree of certainty as will be seen hereafter. We insist upon the fact that we don't speak here of the movements of a minimum more or less loose and vague, but of the continuous and well established path of a perfectly defined and violent typhoon.
Prof. Stephen S. Visher has published in 1923 a very interesting note, a reprint of his article of November 1922 in the Monthly Weather Review of Washington: the title being « Notes on typhoons with charts of normal and aberrant tracks » The chart of abnormal tracks as well as the tables on pages 585 and 586 are very instructive. Almost all the cases collected there tock place to the south of the 25th. parallel; the one now under consideration was traced beyond that latitude, and its complexity and duration are greater than the instances collected in the chart of Mr. S. S. Visher. Here we give at first the description of the trajectory such as we have made it out.