UPDATED: The Eyre Highway has re-opened in both directions between Norseman and Eucla.
Officials have made the decision to re-open the vital road link between WA and the eastern states after it was closed because of flooding rain along the Nullarbor.
Officials will re-assess highway conditions later today.
Although rain is still falling in the flood risk area focussed on Cocklebiddy and Rawlinna, none of the big totals like those of 140mm from Sunday have been repeated.
Motorists have been warned many other roads in the region remain impassible.
A further 40mm was recorded in many areas yesterday after the mighty rains of 140mm and more on Sunday across the Nullarbor.
Tropical moisture is streaming down across Western Australia from the monsoon hit north and the weather system has come to a stand still in south-eastern WA.
The key Trans-Australian Railway remains closed after sections of the line were submerged by floodwaters.
The Australian Rail Track Corporation said work crews would identify whether repairs were needed after the waters receded.
"Given the weather systems intensity and continued rain, it is expected the line will remain closed until later in the week," a spokesman said today.
The rain started falling yesterday at Eucla, on the WA/South Australian border, as the system slowly moved east.
Weather stations on the Eyre Highway at Cocklebiddy and Eyre will likely record more than 200mm over the three days of the record-breaking event.
The Trans-Australian Railway was closed around Rawlinna on Sunday with freight trains stopped by floodwater.
The planned departure of the Indian Pacific from Perth on Sunday was cancelled.
"Due to a severe weather incident on the Nullarbor, the Indian Pacific schedule until Saturday, March 16 has been impacted," Journey Beyond Rail informed customers.
"Guests travelling across these dates have been contacted ... at this time, all departures from Sunday, March 17 will operate as scheduled."
Emergency work crews from the Australian Rail Track Corporation are heading to the area to make damage assessments.
The railway spans 1693km of Australia's normally driest and most isolated terrain.
A national emergency as triggered when the line was cut at Tarcoola in the SA outback in July 2022 and required weeks to repair.
The difference this time is that the rail line from Adelaide splits at Tarcoola to head west across the Nullarbor, and north for Darwin, so both lines were out of action for some time.
The track damage this time, if any is discovered, will be focused on the Perth line.
Flood warnings were issued last night in usually parched areas like Laverton, Balladonia, Cundeelee, Ilkurlka, Warburton, Yelma and Lake Carnegie.
The big rains haven't just been concentrated in the south-east of WA but also across the north where a possible cyclone is forming to cross the Pilbara later in the week.
There are flood warnings in some parts of the Kimberley like Fitzroy Crossing where the Great Northern Highway is closed in both directions to Halls Creek.
Wyndham has recorded 358mm already this month in a late flourish from the wet season.
According to Weatherzone, several computer models are predicting the development of tropical lows or tropical cyclones in the Australian region in the coming week.
A tropical low near the Cocos (Keeling) Islands will move to the east in the coming week towards Australia and has a high chance of developing into a tropical cyclone from Thursday.
If the low develops into a tropical cyclone, this will be the fifth named tropical cyclone this season.
Australia's largest operating sheep station Rawlinna already experienced a deluge early last month and has now been hit by another.
Nestled on the Nullarbor Plain, the station covers an area roughly the size of Sydney and runs more than 30,000 Merinos and welcomed the rain after a long, dry spell.
The station recorded almost 100mm late in January and now has been inundated again by the weekend rain.
There has been wild weather right across the nation over the weekend from unexpected desert flooding to record-breaking heatwaves across eastern Australia.
Much of the wet is being driven by the late arrival of another monsoonal front parked across northern Australia.
BOM says a cyclone could possibly develop south of Christmas Island later in the month and move towards the Pilbara coast later in the week.
For the famously dry Nullarbor and Goldfields areas, forecasters says more rain is likely for these arid areas due to a "stalled synoptic pattern marked by a continuous influx of tropical moisture in the north and west of the country".