SASKATCHEWAN (CBC) - Hurricane Dolly weakened Wednesday afternoon as it hit the Texas coast, making landfall on South Padre Island, just north of the Mexican border.

Dolly was downgraded to a Category 1 storm, the weakest ranking on the five-level hurricane scale, with maximum sustained winds of 150 km/h, according to the U.S. National Hurricane Center. Landfall is when a storm's centre crosses the coastline.

At 1 p.m. ET, the eye of the hurricane was 60 kilometres northeast of Brownsville, Texas.

Officials in low-lying Texas counties had feared the storm would bring torrential rains that could overcome levees holding back the Rio Grande River and cause widespread flooding.

"The levees are holding up just fine," said Cameron County Emergency Management Co-ordinator Johnny Cavazos. "There is no indication right now that they are going to crest."

The storm is expected to bring up to 38 centimetres of rain to parts of southern Texas and northeastern Mexico over the next few days, which could result in flooding in low-lying areas.

About 1,200 National Guard troops were on alert and a disaster declaration was issued for 14 low-lying counties in Texas, but state officials said no evacuations would be ordered unless Dolly reached a Category 3 storm.

In the inland city of San Antonio, about 250 buses were poised to transport coastal residents if needed.

The levees held under similar conditions during Hurricane Beulah in 1967, but have since "seriously deteriorated," Cavazos said.

Late Tuesday, officials closed a causeway connecting Brownsville to the barrier island resort of South Padre Island, which many residents had already left.

A hurricane warning was issued for the Texas coast stretching from Brownsville to Corpus Christi, plus the northeastern coast of Mexico from Rio San Fernando north to the U.S. border.

Across the border from Brownsville, in the Mexican city of Matamoros, police and military vehicles patrolled mostly deserted streets.

About 23,000 people were forced to leave their homes, though some were reluctant due to fears of looting.

"I didn't want to leave because I have been living in the same place for 40 years and I know what this is about," said Arturo Gutierrez, 55, a fisherman from the village of Chichonal who finally agreed to leave. "I am now going to the shelter because my wife forced me to."

The 2008 Atlantic hurricane season is a month ahead of schedule. On average, the fourth tropical storm does not occur until Aug. 29, but Dolly, which formed on July 20, was this year's fourth.

The past two Atlantic hurricane seasons left the United States largely unscathed after a series of powerful hurricanes in previous years, including Hurricane Katrina in 2005.

With files from the Associated Press

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