Q: IS WEATHER, NOT JUST LONG-TERM CLIMATE, A FACTOR?
A: Yes. In September, Antarctica’s sudden stratospheric warming — sort of the southern equivalent of the polar vortex — changed weather conditions so that Australia’s normal weather systems are farther north than usual, Watkins said.
That means since mid-October there were persistent strong westerly winds bringing hot dry air from the interior to the coast, making the fire weather even riskier for the coasts.
“With such a dry environment, many fires were started by dry lightning events (storms that brought lightning but limited rainfall),” Watkins said.
Q: ARE PEOPLE STARTING THESE FIRES? IS IT ARSON?
A: It’s too early to tell the precise cause of ignition because the fires are so recent and officials are spending time fighting them, Flannigan said.
While people are a big factor in causing fires in Australia, it’s usually accidental, from cars and trucks and power lines, Flannigan said. Usually discarded cigarettes don’t trigger big fires, but when conditions are so dry, they can, he said.
Q: ARE THESE FIRES TRIGGERING THUNDERSTORMS?
A: Yes. It’s an explosive storm called pyrocumulonimbus and it can inject particles as high as 10 miles into the air.
During a fire, heat and moisture from the plants are released, even when the fuel is relatively dry. Warm air is less dense than cold air so it rises, releasing the moisture and forming a cloud that lifts and ends up a thunderstorm started by fire. It happens from time to time in Australia and other parts of the world, including Canada, Flannigan said.
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