High Quality Content by WIKIPEDIA articles! The 2010 Western Australian storms were a series of storms that travelled over south-western Western Australia on 21 and 22 March 2010. One of the more intense storm cells passed directly over the capital city of Perth between 3:30pm and 5:00pm on Monday 22 March 2010. It is the costliest natural disaster in Western Australian history, with the damage bill estimated at A$1.08 billion.