Page:Hunt - The climate and weather of Australia - 1913.djvu/159

Rh. 142 143. East Coast Cyclone of Tropical Oceanic Origin.—31st May—2nd June, 1910. This storm was first definitely indicated on the 31st May by falling barometers over New Caledonia and the North Queensland coast, with rain setting in rather extensively over the Central portions of Eastern Queensland. During the next 24 hours heavy rains fell on the coast south from Townsville, and moderate amounts were recorded generally over the south-eastern half of the State. On 2nd June, a definite cyclonic storm was centred off Brisbane immediately south of which some tremendously heavy rain fell. Cleveland had no less than 11.20 inches in the 24 hours. The winds though strong do not seem to have been of exceptional force. The storm continued its southward course for another day, bringing rain to the eastern parts of New South Wales, then moved off towards New Zealand. These storms may occur at any season, and are felt most severely along the coast-line between Brisbane and Sydney, where they develop a wind force and coastal rain production much beyond what their previous history while approaching oversea from the north or north-east would suggest. The steep barometric gradients induced on their south-west quadrants by anticyclonic conditions advancing eastwards over southern Australia probably assist to some extent.

. 144 145. Tropical Cyclone, North Queensland.—10th and 11th February, 1911. Storms of this type in North Queensland are confined in time almost entirely to the summer months, December to April inclusive. They usually strike the coast-line some few degrees further south than the position shown on the 10th, in which case they approach the coast from some point north of east preceded by overcast skies, heavy rain, falling barometers, and freshening winds from between S.S.E. and east. A heavy sea swell, the direction of which is a good index of the position of the storm centre, usually precedes the hurricane winds by some hours.

The storm shown here appears to have developed cyclonically from a depression with very slight gradients which lay over the Gulf of Carpentaria for two or three days previously. As the latitude is but little more than that usually assigned for the origin of tropical cyclones it is probable that the genesis of one is here represented. The chart of the 11th shows the centre further south, about Cardwell; next day it was just inland from Mackay with diminished energy, and it soon after lost its identity altogether. These cyclones usually develop winds of hurricane force between Cooktown and Townsville severe enough at times to wreck buildings. In this case, however, not much damage appears to have been done by wind, but very heavy rains fell—Port Douglas recording 11.88 inches in the 24 hours ending 9 a.m. on the 11th, and the rivers were flooded. These storms are seldom or never experienced with any severity on the New South Wales coastline.