The remote community of Alpurrurulam in the Northern Territory has recorded 250 millimetres of rain since 11pm last night, more than twice its monthly average, and its biggest downpour in more than 10 years. This has taken the four-day rain total beyond 400mm.

The Barkly Tablelands community, about 180 kilometres west of Mount Isa, recorded most of that rain (205mm) in six hours between 11pm and 5am. As a result, flooding has now set in, threatening to isolate Alpurrurulam and nearby Lake Nash Cattle Station. The road in and out, the Sandover Highway, has reportedly already become undrivable in the area.

Image: radar indicating intense rainfall and thunderstorms in the bulls-eyed area of Alpurrurulam.

This latest rain intensity may remind residents of December 2022, when about 350mm fell in four days, cutting off the area from food-truck supplies for weeks. Both the current and December 2022 rain events have less than a one percent chance of occurring in any year.

Whilst the heaviest rain appears to have passed, there is no sign of a lengthy dry spell in the next week. Daily rainfall is expected for at least a week, potentially more than a week-and-a-half. A further 100mm or more is on the cards. Considering how flat the country is, water could be covering the ground well into March.

Image: Access modelled forecast accumulated rainfall for the 84 hours from 3:30am CST Saturday 21 February until 3:30pm CST Tuesday 24 February.

The offending low pressure system is likely to be slow-moving, even becoming stationary at times, continuing to feed off ample tropical moisture, causing daily showers and thunderstorms to completely saturate the ground. The heaviest rain should now become focussed further to the south, likely making the Plenty Highway impassable for the second time in a fortnight.

Travellers are urged to keep up to date with road conditions and Australia Bureau of Meteorology weather warning summary