Page:Hunt - The climate and weather of Australia - 1913.djvu/119

Rh XI..—WEST AUSTRALIAN HURRICANES.

Undoubtedly the most striking feature of the climate of Western Australia is the visitation of the north-west coast by hurricanes, locally known as "willy-willies," in the summer months. These occur in connexion with, or are very violent forms of, cyclonic disturbances which originate over tropical seas, and are practically limited to the summer months—December to April inclusive. "These storms sometimes give the first indication of their approach in the extreme north-eastern corner of the State, and occasionally it is believed at Port Darwin. They travel at first in a south-westerly direction, the centre keeping well out to sea; and their pressure and movement are shown by an easterly wind gradually veering north and west, accompanied by heavy rainfall. When they reach latitude 20° or thereabouts, their course alters and they recurve and commence to travel in a southerly or south-easterly direction, striking the coast generally between Condon and Fortescue, and frequently bring a "willy-willy" to wreck whatever happens to be in the way. They now travel inland, passing, as a rule, either over or to the east of the gold-fields, and bringing more or less rain according to their intensity. Thence they travel to the Southern Ocean."

The path of a typical willy-willy disturbance is shown in Figs. 91-92.

. 91-92.