High Quality Content by WIKIPEDIA articles! The 1947 Sydney hailstorm was a natural disaster which struck Sydney, Australia, on 1 January 1947. The storm cell developed on the morning of New Year`s Day, a public holiday in Australia, over the Blue Mountains, hitting the city and dissipating east of Bondi in the mid-afternoon. At the time, it was the most severe to strike the city since recorded observations began in 1792.