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23. PHENOMENAL HAILSTORM WITH THUNDERSTORM

SYDNEY, 1st January. 1947.

By B.W. Newman B.Sc.

As far as any historical records are available the southern portion of the Sydney metropolitan area was subject to a hailstorm on 1st January 1947, the severity of which was apparently the greatest experienced in that area. From newspaper reports it seems that hail in some cases was in solid lumps up to 4 lb. in weight, but such may have been masses of ice compacted after reaching the ground. There can, however be no exaggeration in the extent of damage caused long it's route, and the wounds inflicted on people in the Bondi Beach area where many surfers were caught unprotected. Numerous houses lost between 20 and 30 tiles from the roof, windows were shattered and motor car hoods holed. In most cases ice lumps were reported to be as large as a cricket ball and the writer is in possession of a mould of one stone almost the size of a tennis ball, the weight of ice in which would have been about 4 ozs. One of our own meteorological personnel also found one columnar-shaped piece approximately 7" x 4" x 4", and the estimated weight of this would be about three pounds.

The storm was first reported from Liverpool (Fig. I) at about 1400K and apparently travelled east-north-east, passing over Mascot at 1425K and Rose Bay at 1435K. Its outer edge passed over the Weather Bureau, Sydney at 1435K. The first definite indication of cloud development at Sydney occurred towards 1300 when cumulus commenced to build in the south and west. By about 1400 this covered the south-west quadrant of the sky and appeared to be moving east, but keeping south of the city. The underpart of the cloud was mottled and serrated or curtained, rather than mammilated and looked angrily black while false cirrus tufts were discernible at the top. Shortly before the rain commenced at the Weather Bureau, shallow cumulus was observed moving from the north-east below the main cloud structure, which was coming from the westward, and between this and the overlaying cloud, considerable turbulence was apparent. At this time there was a terrific noise which appeared to come from the Harbour Bridge as though several trains were passing over. It was definitely not the sound of hail or rain to the south, and it is reasonable to assume its origin was in the cloud. ...../At 1435K the