Houston : Rescue teams in boats, trucks and helicopters scrambled Monday to reach hundreds of Texans marooned on flooded streets in and around the city of Houston before monster storm Harvey returns.
US President Donald Trump promised that the federal government would be on hand to help Texas along the "long and difficult road to recovery" from the historic storm.
The medical examiner's office for Harris County, which includes the city of Houston, confirmed six deaths since Sunday "potentially tied to Hurricane Harvey." Three people were previously known to have died as a result of the storm.
But officials also warned that the danger has not yet passed, with more families still stranded or packed into emergency shelters and the tropical storm once more gathering strength on the Gulf coast.
Houston Mayor Sylvester Turner said more than 8,000 people had been brought, soaking and desperate, to shelters in America's fourth largest city, and defended the decision not to evacuate before Harvey struck over the weekend.
"Search and rescue, that's the number one emphasis, the number one priority for the rest of the day," he said, recalling that around 100 people had died the last time officials tried to empty the city of more than six million.
The 911 emergency line has received more than 75,000 calls, but city officials urged residents facing life-threatening storm water floods to remain on the line and trust that help will come.
Houston fire chief Samuel Pena urged patience, promising: "We fully recognize there are many other people out there in distress situations and we intend to get to every one of them."
Coast Guard commander Vice Admiral Karl Shultz told CNN that he had 18 helicopters in Houston, and weather permitting about 12 in the air at any one time, alongside those of the National Guard.
"If you can get to your roof, wave a towel. Leave a marking on the roof so helicopter crews can see you," he said, describing the volume of emergency calls as "staggering.
