Tropical storm Humberto, which grew faster than any storm on record from tropical depression to full-scale hurricane, surprised the Texas-Louisiana coast with 85-mph (137-kph) winds and heavy rain that knocked out power to more than 100,000 and left at least one person dead.
Meanwhile, Tropical Storm Ingrid formed late Thursday in the open Atlantic Ocean, but it was far from land.
Meteorologists were at a loss to explain the rapid, 16-hour genesis Thursday of Humberto, the first hurricane to hit the U.S. since 2005.
"Before Humberto developed, you looked at the satellite imagery the day before, and there was virtually nothing there. This really spun up out of thin air, very, very quickly, said National Hurricane Center specialist James Franklin in Miami. "We've never had any tropical cyclone go from where Humberto was to where Humberto got."
Surprising as Humberto was, forecasters said it may have been a blessing that it did not linger longer over warm waters of the Gulf of Mexico, which could have given it time to develop into more than a minimal hurricane.
Texas coastal residents prepared for a tropical storm rainmaker that would quickly flood the ground already saturated from the wettest summer in 60 years. Although forecasts called for up to 1 foot (30 centimeters) of rain, Humberto produced no more than half that and generated much more wind. By late afternoon, it had weakened to tropical depression churning across the southern U.S.
"We feel very fortunate and blessed it wasn't worse," said Beaumont resident Edward Petty, 50, who was clearing debris outside his home 50 miles (80 kilometers) northeast of High Island, near where the storm came ashore.
"It was amazing to go to sleep to a tropical storm and wake up to a hurricane," he said. "What are you going to do? You couldn't get up and drive away. You couldn't run for it. You just have to hunker down."
The only reported death was a man who died in southeast Texas when the carport at his home collapsed, police said.
Humberto made landfall less than 50 miles (80 kilometers) from where Hurricane Rita did in 2005, and areas of southwest Louisiana not fully recovered from Rita were bracing for more misery.