User:Daniel/Sandbox/1990 Sydney hailstorm

The 1990 Sydney hailstorm was, at the time of the event, the costliest storm in Australian history. The hailstorm, which meteorologists suggest may have been a supercell, struck the New South Wales capital of Sydney during the afternoon of March 18, 1990, causing severe damage in a corridor through the greater western and northern beaches regions of the city.

The storm spawned in the Southern Tablelands region of the state in the early afternoon, before reaching the Liverpool area—the location of the most severe damage—just over two hours later. The cell, which moved at an average velocity of 44 km/h, produced hail up to 8 cm in diameter as well as violent winds and heavy rainfall.

Insured damages caused by the storm were over A$314 million, with the total damage bill (including uninsured damages) estimated to be around A$450 million, both in 1990 figures. The cell affected 130 postcodes of Sydney, although 20% of insured damages occurred in just two. In addition to 25 injuries caused by the event, over 14,000 homes and 9,000 cars incurred damage from the hailstones, wind and rain.

Conditions and climatology
The severe thunderstorm season for Sydney is generally considered to be between the months of X and Y, with a peak in Z. During this time, conditions along the east coast of Australia are highly conducive for the formation of hailstones within these severe thunderstorms. The variation of air temperature in the atmosphere with warm and humid air close to the ground and colder air above it causes instability, and the cold upper atmosphere temperatures allow the precipitation to fall in solid form as hailstones.

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