Australia's weather radar spent a month forecasting rain that turned out to be moths
Radars across south-eastern Australia have lit up with 'rain' every night for weeks. The skies were clear. The culprit: millions of migrating bogong moths.
If you’d checked the rain radar in New South Wales any evening last month, you’d have reached for your brolly. You’d also have been wrong.
For weeks, weather radars across south-eastern Australia have lit up with what looks like widespread drizzle, like clockwork, just after sunset. On most nights the skies were clear, and it certainly hadn’t rained for a month straight.
The equipment isn’t broken, and – the Australian Broadcasting Corporation’s meteorologist felt it necessary to clarify – it’s “not a giant UFO” either. It’s millions of bogong moths migrating south to the Australian Alps for summer. Radars bounce radio waves off anything in the sky, and a big enough swarm of moths looks remarkably like light rain.
“Large numbers of insects can look like very light widespread rain, particularly near sunrise and sunset,” the Bureau of Meteorology explained. The phenomenon has now spread into Victoria too.
Proper forecasts are fine, since they rely on models, ground observations and satellites. But some weather apps working from raw radar data may have been sending false rain alerts.
It isn’t the moths’ first offence. At the 2000 Sydney Olympics, forecasters panicked when radar showed rain heading for the closing ceremony – until a large moth landed on the opera singer Yvonne Kenny live on television. Mystery solved, dignity lost.
