Australia faces a dual severe tropical cyclone strike this weekend starting with Trevor in the Northern Territory

By Kristina Pydynowski, AccuWeather senior meteorologist

As Veronica threatens to cause a flood disaster in northwestern Australia, the dangers to lives and property are expected to expand well away from where Severe Tropical Cyclone Trevor makes a dangerous strike on Australia's Northern Territory early this weekend.

After making landfall on the Cape York Peninsula on Tuesday, Trevor has rapidly strengthened into a powerful Category 4 severe tropical cyclone (the equivalent of a Category 4 major hurricane in the Atlantic Ocean) over the warm waters of the Gulf of Carpentaria.

This will only be the second time in Australia's history that there will be two Category 4 or above cyclones making landfall withing 24 hours of each other, according to Australia's Bureau of Meteorology.

Trevor will remain that strong as it blasts onshore east of the Pellew Islands with destructive winds and flooding rain on Saturday morning, local time. An inundating storm surge will occur near and east of where the cyclone slams onshore.

Trevor will blast onshore near the Pellew Islands with destructive winds and flooding rain. An inundating storm surge will occur near and east of where the cyclone slams onshore.

The dangers prompted a state of emergency to be declared in the Northern Territory, according to the Australian Broadcasting Corporation (ABC). The largest mass evacuation in the state since Cyclone Tracy in 1974 was performed by the Australian Defence Force.

Many residents of Groote Eylandt and Borroloola were transported by aircraft to Darwin. Other people have been transported out of the area by bus.

While the worst of Trevor is expected to bypass Groote Eylandt, damage to well-built homes, widespread tree damage and prolonged power cuts can occur in Borroloola on Saturday.

This satellite image shows the dual severe tropical cyclones, Trevor and Veronica, churning near northern Australia on Friday, March 22, 2019. (CIRA/Himawari)

Once Trevor is on land and away from water (its fuel source), its powerful winds will quickly weaken. The dangers in terms of flooding, however, will not lessen.

Heavy rain from Trevor is anticipated to sweep across more of the Northern Territory and into northeastern South Australia and southern Queensland Sunday and into Tuesday.

Rainfall along this swath can total 100-200 mm (4-8 inches) with an AccuWeather Local StormMax™ of 300 mm (12 inches).

In the desert locations such as Birdsville, these totals would mean that a nearly a year's worth of rain can pour down in one to two days.

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With the soil unable to absorb that much rain, the rapid runoff can lead to major flooding. Canyons and normally dry washes or arroyos can suddenly fill with fast-flowing water, threatening to sweep away anyone or thing in its path. Mudslides can be triggered along hillsides.

Residents and motorists should avoid these areas and evacuate to safe locations if your home is in a danger area.

The flooding and mudslides may lead to road closures and damaged bridges.

The river channels recently filled up with water as runoff from the flooding rain earlier this winter flowed down into the region.

"Trevor's moisture and downpours may get pulled southeastward into northern New South Wales and southern Queensland, including Brisbane and perhaps Sydney, later next week," according to AccuWeather Senior Meteorologist Jason Nicholls.

Worse than causing disruptions to travel and outdoor activities, the most persistent downpours can trigger flash flooding.

Trevor first slammed the Cape York Peninsula earlier this week, causing damage to some homes, power cuts and flooding. The entire communities of Coen and Lockhart River lost power during the storm.

Lockhart River Mayor Wayne Butcher found it ironic that his home was the only one in the town damaged by the cyclone, according to ABC.

On the other side of Australia, Severe Tropical Cyclone Veronicathreatens to cause a flood disaster along a part of the Pilbara coast later this weekend and early next week.

Download the free AccuWeather app to remain aware of all the tropical dangers threatening Australia.