Thousands of Australians are hunkering down in Houston and other parts of southern Texas as tornadoes, historic amounts of rain and catastrophic flooding from tropical storm Harvey hit the region.
With as much as 1.27m of rain forecast in some areas, Australia's Department of Foreign Affairs and Trade is urging Australians to follow the advice of local authorities and monitor media reports.
Coast Guard helicopters are rescuing residents from rooftops, more than 215 highways in Texas have been closed and 3000 national guard troops have been activated.
Houston is America's energy capital and the site of US headquarters for Australian companies including BHP Billiton, Santos and Woodside.
"The roads are basically a system of rivers right now," Geelong native David Bryant, who is holed up in his three-storey townhouse in a southern suburb of Houston, told AAP on Sunday.
Mr Bryant, 41, who works for BHP Billiton in Houston, took in a friend, his seven-months pregnant fiancee and their cats after they had to flee their home in a different suburb when a tornado struck a short distance away and floods threatened.
"We're planning to just stick tight here," Mr Bryant said.
"We have plenty of food and water and have not lost power yet."
With mobile phone coverage and internet still working despite the carnage, Mr Bryant, who is president of the Houston Lonestars Aussie rules club, has been able to keep in touch with his Australian teammates and other expatriates.
Another Australian, Morgan Hughes, a co-owner of Houston's Platypus Brewing pub, said his home was in the elevated suburb, The Heights, but he was cut off from the brewery.
He could monitor the pub via surveillance cameras and it appeared to have also avoided the flooding.
"A lot of Australians live in The Heights as well and it has become its own island right now so I can't get to the brewery," Mr Hughes said.
"I've checked in on all of our staff and friends and they have hunkered down and most are fine but some have had some issues.
"I have one Aussie mate who has water in his house.
"It is going to continue be pretty rough."
Harvey, which hit the Texas coastline on Friday as a category 4 hurricane with 209 km/h winds, has developed into a slow-moving tropical storm that is dumping unprecedented levels of rain on the region.
