Mining companies operating in the north-west of Australia can expect a higher than average tropical Cyclone season according to Bureau of Meteorology’s just released Outlook for 2017 to 2018
According to the BOM report the North-western sub-region of Australia has a 56% chance of more tropical cyclones than average and a 44% chance of fewer tropical cyclones than average.
Typically, five cyclones form in or pass through this area each season. Around 40% of tropical cyclones, or their associated tropical lows, effect coastal areas of the North-western sub-region. Outlook accuracy for this region is moderate.
However, BOM is forecasting an average season for most of the country.
A typical Australian tropical cyclone season – which runs from November to April – sees between 10 and 13 cyclones occurring in Australian waters, with around four of these crossing the coastline.
BOM’s Senior Climatologist Dr Paul Gregory said tropical cyclones can occur at any time throughout the season and even tropical cyclones well offshore can have significant impacts on coastal areas due to storm surges and rough seas.
“While the tropical cyclone outlook points to a typical season, as we saw earlier this year with severe tropical cyclone Debbie, one event can have a devastating effect on a number of communities.
“It is rare that cyclones are evenly spread across the season. Last season saw only one tropical cyclone form before mid-February – which was a very late start. But then eight subsequent cyclones in the region brought the season’s total to nine.
When Tropical cyclone Blanche crossed the West Australian coast on 6 March, it was the latest date that the first cyclone had crossed the coast on record.
“Tropical lows also form during the severe weather season. While these may lack the damaging winds and storm surges of cyclones, they can still cause widespread and very intense rainfall and dangerous flooding,” he said.
BOM said that neutral to weak La Niña conditions in the tropical Pacific Ocean, and slightly warmer-than-average ocean temperatures to the north and east of Australia, are affecting this season’s outlook.
BOM is predicting the Western region is likely to experience an average number of tropical cyclones this season, with the likelihood of more than average at 52%. The chance of fewer than average is 48%. Typically between about 15% and 40% of tropical cyclones in the Western region create coastal impacts. Outlook accuracy for the Western region is low.
The Northern region outlook suggests an average number of tropical cyclones with a 53% chance of more tropical cyclones than average and a 47% chance of fewer tropical cyclones than average. In a typical year the Northern region experiences around three cyclones, and one or two tropical lows that later become cyclones after moving into the Western or Eastern regions. About three-quarters of the tropical cyclones in the Northern region impact coastal regions. Outlook accuracy for this region is very low.
The Eastern region outlook shows a near average season is most likely, with a 54% chance of more tropical cyclones than average and a 46% chance of fewer. About a quarter of tropical cyclones in the Eastern region make landfall. Outlook accuracy for this region is low.