Officials fear massive flooding from Dolly

Dolly spun into a hurricane Tuesday, heading toward the U.S.-Mexico border and the heavily populated Rio Grande Valley, where officials feared heavy rains could cause massive flooding and levee breaks.

Dolly was upgraded from a tropical storm Tuesday afternoon with sustained winds near 75 mph, and some strengthening is forecast before landfall today.

A hurricane warning was issued for the coast of Texas from Brownsville to Corpus Christi and in Mexico from Rio San Fernando northward. At 11 p.m. EDT, the storm's center was about 110 miles east-southeast of Brownsville, moving northwest at about 9 mph.

In Mexico, Tamaulipas Gov. Eugenio Hernandez said officials are planning to evacuate 23,000 people to shelters.

Texas officials urged residents to move away from the Rio Grande levees because – if Dolly continues to follow the path of 1967's Hurricane Beulah – “the levees are not going to hold that much water,” said Cameron County emergency coordinator Johnny Cavazos.

Bands of rain began to pass over South Padre Island and Reynosa, Mexico, on Tuesday afternoon, and the surf roughened. Forecasters predicted Dolly would dump 15 to 20 inches of rain and bring storm surge flooding of 4 to 6 feet above normal high-tide levels.

Tropical storm warnings were issued for areas adjacent to the hurricane zone, and Gov. Rick Perry declared 14 South Texas counties disasters, allowing state resources to be used to send equipment and emergency workers to areas in the storm's path.

The storm, combined with levees that have deteriorated in the 41 years since Beulah swept up the Rio Grande, pose a major flooding threat.

In the Gulf of Mexico, Shell Oil evacuated workers from oil rigs, but said it didn't expect production to be affected by the storm.