High Island, Texas: Humberto, which grew faster than any storm on record from tropical depression to full-scale hurricane, surprised the Texas-Louisiana coast with 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 on Thursday in the open Atlantic Ocean, but it was far from land.

Meteorologists were at a loss to explain the rapid, 16-hour genesis on Thursday of Humberto, the first hurricane to hit the US 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 Centre specialist James Franklin in Miami.

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 made it worse.

Texas residents who prepared for a rainmaker storm were, however, spared the flooding after it did not pour as per forecasts.