More than 30,000 people are expected to be housed in shelters as monster storm Harvey continues to devastate the Texas city of Houston and surrounding areas, a top federal emergency official said Monday.

Widespread flooding unleashed by deadly storm Harvey left Houston -- the fourth-largest U.S. city -- increasingly isolated Monday, with airports and highways closed and residents being rescued from their inundated homes by boat and helicopter.

Bryan Curtis normally rides his jet ski for fun. On Sunday, he turned it into an emergency rescue vehicle.

Curtis -- who lives in Conroe, a little to the north of Houston -- was one of the many civilians who pitched in to help evacuate those stranded in rapidly rising floodwaters in Texas's biggest city unleashed by monster storm Harvey.

Tropical Storm Harvey unleashed catastrophic flooding in Houston Sunday, turning streets in Texas' largest city into raging rivers as trapped residents climbed to higher floors and the death toll rose.

The head of the U.S. office for disaster preparedness urged residents of Texas Friday to get out of the path of Hurricane Harvey, warning of an impending "disaster" from the powerful storm.

"Texas is about to have a very significant disaster," said Brock Long, director of the Federal Emergency Management Agency, speaking to CNN.

South Africa's first online auction of rhino horn opened Wednesday, despite protests by conservation groups that the legal, domestic sale would encourage poachers.

Fukushima's operator on Tuesday started freezing the last section of a $320 million ice wall designed to combat widespread water contamination at the site of the worst nuclear accident in a generation.

More than 750 people have died in floods across South Asia, officials said Monday, with monsoon rains also causing the deaths of hundreds of animals, including rhinos and a tiger.

Tropical Storm Gert surged late Monday to become the second hurricane of the Atlantic season, the National Hurricane Center said.

For now, the storm posed no risk to land as it was far from Bermuda, the NHC said at 2300 GMT in Miami.

Last year's global weather was far more extreme or record-breaking than anything approaching normal, according to a new report.

The U.S. National Oceanic and Atmospheric Administration on Thursday released its annual checkup of the Earth, highlighting numerous records including hottest year, highest sea level, and lowest sea ice in the Arctic and Antarctica.