Seis meses de lodo—six months of mud.
Seis meses de polvo—six months of dust.
Seis meses de todo—six months of everything.
The northern islands lie in the track of the typhoons which, developing in the Pacific, sweep over the China Sea from NE. to SW. during the southwest monsoon. They may be looked for at any time between May and November, but it is during the months of July, August, and September that they are most frequent. Early in the season the northern region feels the greatest force, but as the season advances the typhoon gradually works southward and the dangerous time at Manila is about the end of October and the beginning of November. Typhoons rarely, if ever, pass south of 9 degrees N. latitude. Sometimes the typhoon is of large diameter and travels slowly, so far as progressive movement is concerned; at others it is of smaller dimensions, and both the circular and progressive motions are more rapid. However they are always storms of terrific energy and frequently cause terrible destruction of crops and property on shore and of shipping at sea. Thunderstorms, often of great violence, are frequent in May and June, before the commencement of the rainy season. During July, August, September, and October the rains are very heavy. The rivers and lakes are swollen and frequently overflow, flooding large tracts of low country.
At Manila the average rainfall is stated to be from 75 to 120 inches per annum, and there the difference between the longest and shortest day is only 1 hour 47 minutes and 12 seconds. This rainfall, immense though it be, is small as compared with that of other parts of the archipelago; e.g., in Liano, NE. of Mindanao, the average yearly downpour is 142 inches.
Gales.—The gales of the Philippines may be divided into three classes, known by the local names of Colla, Nortada, and Baguio. The Colla is a gale in which the wind blows constantly from one quarter, but with varying force and with alternations of violent squalls, calms, and heavy rains, usually lasting at least three days; these gales occur during the southwest monsoon and their direction is from the southwest quarter. The Nortada is distinguished from the Colla, in that the direction is constant and the force steady, without the alternations of passing squalls and calms. The Nortada is generally indicative that a typhoon is passing not very far off. These gales occur chiefly in the northern islands, and their direction, as the name implies, is from the northward. Baguio is the local name for the revolving storm known as the typhoon, which, being the more familiar term, will be used in these notes.
Typhoons.—These storms have their origin to the east or to the southeast of the Philippines, whence their course is westward, with a slight divergence to the north or south, the average direction appearing to be west by north. They occur in all months of the year, but the greater number take place about the time of the equinoxes. The most violent ones occur at the autumnal equinox, and on an average, two or three occur every year, and sometimes one follows another at a very short interval. It is believed that when one of these typhoons passes a high latitude in September there will be another in October of that year, and one may be looked for in November in a lower latitude. These tempests are not encountered in latitudes below 9 degrees N. The rate of progress of these storms is about 13 miles an hour; in none of those observed has it exceeded 14 miles nor fallen below 11 miles. The diameter of the exterior revolving circle of the storm varies from 40 to 130 miles, and the diameter of the inner circle or calm region, may be estimated at from 8 to 15 miles. The duration of the true typhoon at any one place is never longer than ten hours and generally much less. These storms are always accompanied by abundant rain, with low, dense clouds, which at times limit the horizon to a few yards distance, and are generally accompanied by electrical discharges. The barometer falls slowly for some days before the typhoon, then falls rapidly on its near approach, and reaches its lowest when the vortex is but a little way off. It then rises rapidly as the vortex passes away, and then slowly when it has gained some distance. Near the vortex there are usually marked oscillations. The typhoon generally begins with a northerly wind, light drizzling rain, weather squally and threatening, a falling barometer and the wind veering to the eastward, when the observer is to the northward of the path of the storm, and backing to the westward when he is to the southward of it; the wind and rain increase as the wind shifts, and the storm generally ends with a southerly wind after abating gradually.
The following warnings of the approach of a typhoon, and directions for avoiding the most dangerous part of it, are taken from the China Sea Directory: The earlier signs of a typhoon are clouds of a cirrus type, looking like fine hair, feathers or small white tufts of wool, traveling from east or north, a slight rise in the barometer, clear and dry weather, and light winds. These signs are followed by the usual ugly and threatening appearance of the weather which forbodes most storms, and the increasing number and severity of the gusts with the rising of the wind. In some cases one of the earliest signs is a long heavy swell and confused sea, which comes from the direction in which the storm is approaching and travels more rapidly than the storm's center. The best and surest of all warnings, however, will be found in the barometer. In every case there is great barometric disturbance. Accordingly, if the barometer falls rapidly, or even if the regularity of its diurnal variation be interrupted, danger may be apprehended. No positive rule can be given as to the amount of depression to be expected, but at the center of some of the storms the barometer is said to stand fully 2 inches lower than outside the storm field. The average barometric gradient, near the vortex of the most violent of these storms, is said to be rather more than 1 inch in 50 nautical miles. As the center of the storm is approached the more rapid become the changes of wind, until at length, instead of its direction altering gradually, as is the case on first entering the storm field, the wind flies around at once to the opposite point, the sea meanwhile breaking into mountainous and confused heaps. There are many instances on record of the wind suddenly falling in the vortex and the clouds dispersing for a short interval, though the wind soon blows again with renewed fury.
In the northern hemisphere when the falling barometer and other signs create suspicion that a typhoon is approaching, facing the wind and taking 10 or 12 points to the right of it, will give the approximate bearing of its center. Thus, with the wind NE., the center will probably be from S. to SSE. of the observer's position. However, it is difficult to estimate the center of the vortex from any given point. This partly arises from the uncertainty as to the relation between the bearing of the center and the direction of the wind, and greatly from there being no means of knowing whether the storm be of large or small dimensions. If the barometer falls slowly, and the weather grows worse only gradually, it is reasonable to suppose that the storm center is distant; and conversely, with a rapidly falling barometer and increasing bad weather the center may be supposed to be approaching dangerously near.
Practical Rules.—When in the region and in the season of revolving storms, be on the watch for premonitory signs. Constantly observe and carefully record the barometer.
When on sea and there are indications of a typhoon being near, heave to and carefully observe and record the changes of the barometer and wind, so as to find the bearing of the center, and ascertain by the shift of the wind in which semicircle the vessel is situated. Much will often depend upon heaving to in time. When, after careful observation, there is reason to believe that the center of the typhoon is approaching, the following rules should be followed in determining whether to remain hove to or not, and the tack on which to remain hove to:
In the northern hemisphere, if the right-hand semicircle, heave to on the starboard tack. If in the left-hand semicircle, run, keeping the wind if possible, on the starboard quarter, and when the barometer rises, if necessary to keep the ship from going too far from the proper course, heave to on the port tack. When the vessel lies in the direct line of advance of the storm—which position is, as previously observed, the most dangerous of all—run with the wind on the starboard quarter. In all cases increase as soon as possible the distance from the center, bearing in mind that the whole storm field is advancing.