The extreme weather experienced by much of Australia during the Christmas break really did bring the tropics to Melbourne, the Bureau of Meteorology has said.
In a report released on Monday, the bureau said the December 2016 weather event was largely unprecedented, breaking numerous records and bringing conditions to Melbourne which were “more characteristic of Darwin at the peak of the wet season than of southern Australia”.
In its report, the bureau said the precipitable water levels – the amount of water in the atmosphere – broke multiple records in all states and territories except New South Wales.
Dewpoints, which are an indication of humidity, were similarly extraordinary, with South Australia’s Marree (27.6°) and Geelong in Victoria (26°) seeing levels which the bureau said would be “very high values even for tropical locations”.
Blair Trewin, senior climatologist with the bureau said a dewpoint over 20° was “pretty humid by Melbourne standards”. “To put it into context, 20° is a fairly typical dewpoint for Brisbane in mid summer,” he told Guardian Australia. Levels of 26 to 27 were more typical for Darwin, he said.
The wild weather began a few days before Christmas as a tropical low formed off the coast of the Northern Territory, causing a monsoon event before moving towards the Kimberley.
On Christmas day it combined with the remnants of tropical cyclone Yvette and made its way slowly through the centre of Australia, causing floods in the Kimberley and central Australia, including at Uluru, which was closed by Parks Australia. A tourist was found alive after his car was swept away by flood waters in Alice Springs, and a group of people were rescued after they went missing while attempting to travel between two outback communities.
Heavy thunderstorms also caused flash flooding in South Australia and Victoria, with Melbourne among the areas most affected.
There were few recorded precedents for the tropical weather event to reach so far southeast, the bureau said. “Probably the most directly comparable event was one we had in January 2011, the same time as the floods in Brisbane which got all the attention,” said Trewin. “That 2011 event also saw major flooding in northern Victoria.”
The highest December rainfalls remained in the north, with totals of more than 400mm in some places, but south-eastern areas also received extensive rains and South Australia saw its wettest December on record.
The heaviest fall occurred in the remote community of Kintore, with 231.6mm on Boxing Day, surpassing its highest December rainfall record, set in 1975. Almost 100 people were evacuated, with a number of houses damaged and roads made impassable by the rains.
Broome also broke its December record, with 225.6mm on 23 December, and Adelaide had its third wettest December day on record, with 61.2mm.
Overnight minimum temperatures were significantly high during the period, with the most extreme warmth in eastern NSW, where several places saw highest December minimum temperatures on record.
Adelaide also had its hottest Christmas Day in 71 years, reaching 40.7C – hotter than any capital city in the country that day.
The weather event bookended a year of climate extremes. The bureau’s annual climate statement pointed to a strong El Niño and civilisation’s penchant for burning fossil fuels as explanation for a year of extraordinary weather, devastating ecosystems around the world.
