Drowning sign shows Australia's gnarly weather whiplash

Here's a vivid show of weather whiplash: After Australia experienced both its driest and hottest year ever recorded in 2019, the nation's fire-ravaged eastern states have now been hit with torrential deluges and epic floods.

The February rains, dumping nearly 14 inches (350 mm) over 24 hours in some places, have resulted in the region's highest multi-day rainfall totals in three decades.

Extreme flooding has ensued. A picture tweeted on Sunday by the New South Wales Rural Fire Service depicts, ironically, a bushfire warning sign being drowned by murky floodwaters.

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The good news is the rains have extinguished many giant fires, some of which have burned since October. The Gospers Mountain megafire, which by the end of 2019 had already burned 1.2 million acres, is finally "out," according to the Rural Fire Service.

As Australia's science agency, CSIRO, notes, it's normal for Australia to have big year-to-year differences in rainfall. But, critically, the agency says "There is evidence that some rainfall extremes are becoming more intense."

More intense rainfall is caused by a warming climate. It's simple physics. As the atmosphere warms, it can hold more water — resulting in more extreme deluges. It's the same reason why rainfall extremes have grown increasingly intense in the U.S., leading to a boost in flooding.

Though rainfall events are becoming more extreme in big swathes of Australia, overall rainfall has declined significantly in southeastern Australia over the last twenty years, setting the stage for parched bushlands that are significantly more likely to burn — resulting in megafires. This dry vegetation, combined with an increase in hot and dry fire weather, almost certainly means larger and more sustained fires in Australia in the decades ahead.

Regarding bushfires and flooding, Australia's Department of Home Affairs concluded that with a "driver of a changing climate there is growing potential for some natural hazards to occur at unimagined scales, in unprecedented combinations and in unexpected locations."