"Descending squalls" come slanting downwards, off high land,[27] or from upper regions of atmosphere. They are dangerous, being sometimes violently strong.
A squall cloud that can be seen through or under is not likely to bring, or be accompanied by, so much wind as a dark continued cloud extending beyond the horizon. How the comparative hardness or softness of clouds foretells more or less wind or rain, was stated in pages 13 and 14.
The expressions "hardening up," "softening," or looking "greasy," are familiar to seamen: and such very sure indications are the appearances so designated, that they can hardly be mistaken.
The rapid or slow rise of a squall cloud--its more or less disturbed look--that is, whether its body is much agitated, and changing form continually, with broken clouds, or scud, flying about--or whether the mass of cloud is shapeless and nearly quiet, though floating onwards across the sky--foretells more or less wind accordingly.
An officer of a watch, with a good eye for clouds and signs of changing weather, may save his men a great deal of unnecessary exposure, as well as work, besides economising sails, spars, and rigging.
In some of the "saws" about wind and weather, there is so much truth that, though trite and simple, their insertion here can do no harm.
Adverting to the barometer:-- When rise begins, after low, Squalls expect and clear blow. Or:--_First_ rise, after very low, Indicates a stronger blow. Also:--Long foretold, long last: Short notice, soon past. To which may be added:--In squalls-- When rain comes before wind, Halyards, sheets, and braces mind. And:--When wind comes before rain, Soon you may make sail again.
Also, generally speaking:-- When the glass falls low, Prepare for a blow; When it rises high, Let all your kites fly.[28]
To these short expressions--well known, in practice, to the experienced; a very concise but sure rule may be added, for avoiding the central or strongest part of a hurricane, cyclone, typhoon, tornado, or circling storm.
With your face towards the wind, in North latitude, the centre of the circling, or rotatory storm, will be square to your right. In South latitude, square to your left.
The apparent veering of the wind, and the approach or retreat of the dangerous central circle, depend on your position in the curvilinear whirl or sweep.