The Black Thursday bushfires were the largest ever recorded in Australia, and were caused in part by an intense drought that had occurred throughout 1850. On 6 February 1851, a strong furnace-like wind came down from the north and gained power and speed as the hours passed. It is believed that the disaster began in the Plenty Ranges when bullock drivers left logs burning unattended, which set fire to long, dry grass affected by the recent drought. Approximately 5 million hectares, or a quarter of Victoria, was burnt. Twelve human lives were lost, along with one million sheep, thousands of cattle and countless native animals.