A summer of cyclones: What's to come for Australia this season
As if 2020 hasn’t dealt us a tough enough hand, Australia can expect more cyclones than usual over the next few months, according to the Bureau of Meteorology Tropical Cyclone Outlook.
There’s a 66 per cent chance of more tropical cyclones than average, between November 2020 and April 2021, according to the outlook prediction.
Usually, just four cyclones cross the Australian coast in a season; this year we could be looking at six or more.
Already this summer we have seen Cyclone Yasa devastate Fiji. It reached category five strength and has been the strongest cyclone for 2020 in the region. Monsoonal conditions in northwest Australia also threatened to develop into cyclones during December.
What is a tropical cyclone?
“Cyclones are low pressure systems that form over warm tropical waters,” Bureau of Meteorology climatologist, Tamika Tihema, told Yahoo News Australia.
“They usually form when the sea-surface temperature is above 26.5°C. They dissipate when they move over land or cooler oceans.”
Why are we likely to see more cyclones this summer?
“Because La Niña conditions are active in the tropical Pacific Ocean,” Ms Tihema said.
La Niña was declared active in September, and “this means we can expect more rain, higher than usual sea temperatures, and increased cyclones as part of the climate phenomenon,” she said.
“Average to warmer-than-average ocean temperatures to the north of Australia have influenced this year's tropical cyclone outlook.”
In a normal year, Australia gets between nine and 11 cyclones, with just four making landfall, usually in January.
This year, the Bureau of Meteorology has predicted there’s a 66 per cent chance of more cyclones than average for Australia.
La Niña also brings forward cyclone season, with the first cyclone often crossing the coast in December, rather than January.
What is La Niña?
La Niña is a climate phenomenon that increases the conditions which allow tropical cyclones to brew.
This includes warmer ocean temperatures, which cause greater evaporation, stronger trade winds and more rain in the West Pacific.
Oceans swap between La Niña and its counterpart El Niño every two to seven years, depending on the wind and ocean conditions across the Pacific Ocean.
Where will the cyclones hit?
“There are always tropical cyclones in the Australian region in the severe weather season – regardless of La Niña,” Ms Tihema said.
“Cyclones form in northern Australia, and affect Western Australia, the Northern Territory and Queensland.”
How else will La Niña affect our weather?
La Nina brings with it an “increased chance of widespread flooding and earlier first rains across northern Australia,” Ms Tihema said.
The climate phenomenon can also cause longer, but less intense heatwaves across southeast Australia, and an increased chance of heatwaves around Western Australia.
What else we can expect from this summer's weather?
The heavy rain that eastern parts of Australia have recently experienced is here to stay for the season, Ms Tihema said.
“The climate outlook suggests January to March is likely to have above average rainfall across much of the country – particularly in the eastern states, with strongest chances of above median rainfall in eastern Queensland,” she said.
“Maximum temperatures for January to March show little shift towards being above or below average for much of the country, and minimum temperatures for this same time period are very likely to be above average across much of Australia.”
How are cyclones measured?
Cyclones are measured in categories, with one being the weakest, and five being the strongest.
A category one cyclone has winds that are less than 125km/h and can cause some damage to crops and trees.
A category five cyclone has wind gusts over 279km/h with an average wind blowing at around 200km/h, and can cause widespread destruction.
What are the worst cyclones Australia has seen?
In 1899, Cyclone Mahina hit Princess Charlotte Bay in Queensland, and it’s believed over 400 people were killed, making it Australia’s deadliest natural disaster.
Most of the people who died were on pearling ships, and it’s believed 100 of them were Indigenous Australians.
In 1975, category 5 Cyclone Joan recorded wind gusts of 208km/h in Port Hedland, 600km South-West of Broome. There were no lives lost but it caused around $25million of damage to property and public facilities.
In recent years, the worst cyclone Australia has seen was Yasi, in 2011, which hit Queensland’s Mission Beach and Hinchinbrook Island.
The cyclone was 1450km in diameter, and recorded wind gusts of 285 km/h. It destroyed crops of bananas and sugar cane, as well as enormous areas of trees and buildings.
Only one person was killed, after they took shelter in a building and were suffocated by generator fumes.
What are the economic repercussions of cyclones?
Cyclones can have huge economic consequences.
Cyclone Yasi is believed to have cost around $3.6 billion in terms of damage and effects on local produce.
Because Northern Queensland supplies around 85 per cent of the country’s bananas, when the crops were wiped out, this had a knock-on effect, raising the price of bananas nationwide and costing banana farmers around $350 million.
North Queensland produces around 20 per cent of Australia’s sugar cane, but the damage to crops cost farmers an estimated $500 million in lost revenue, and caused prices across the country to spike to a 37-year high.
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Cyclone Yasi also caused widespread damage to public infrastructure, estimated to be around $5 million, as well as private property, prompting $225 million of insurance claims.
It also had a huge impact on the local tourism industry, preventing people from visiting Innisfail and Cardwell as a gateway to the Great Barrier Reef.
How should you prepare your home for a cyclone?
First of all, create a cyclone plan so you know exactly what to do if a cyclone hits.
Prepare an emergency kit that includes a battery powered radio.
Find out from your local council if your home is built to cyclone standards, and check with your insurance provider that you’re covered for flooding and cyclone damage, clean-up and debris removal.
Then, repair any loose tiles, or anything that isn’t secured properly on the roof or walls of your home.
Cut any branches or trees hanging over or near your house, and secure items such as boats, trailers, rainwater tanks, solar panels and garden sheds.
If you hear a Standard Emergency Warning Signal, which is broadcast when a cyclone is 12 hours or less away, either secure shutters on windows or tape them in a cross-hatch pattern with strong packing tape. Bring children and pets indoors, and bring outdoor furniture or loose items such as gardening equipment indoors.
Ensure you have at least three litres of water per person per day for at least three days, fill buckets and baths with water, and ensure you have water purification tablets incase your water is cut off.
If an official evacuation order is issued, follow directions immediately, either staying inland or finding public shelter.
During a cyclone, turn off all electricity, gas and water, and unplug all appliances. Make sure everyone is sheltered in the strongest part of the house and if the building starts to be damaged, shelter under a strong table or bench.
Stay inside until you’re told it’s safe. Even when winds may appear calmer, it may just mean you’re in the eye of the cyclone; once this passes the eye wall is where the strongest winds and heaviest rainfall occur.
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