BROWNSVILLE, Texas -- Before being downgraded to a tropical storm, Dolly barreled into South Texas on Wednesday, lashing the coast with winds up to 100 mph and dumping heavy rain that flooded some low-lying areas but spared levees along the heavily populated Rio Grande Valley.

Hurricane Section | Dolly Downgraded

At 11 p.m. EDT Wednesday, the center of the storm was about 55 miles northwest of Brownsville, Texas. The storm is moving west near 7 miles per hour.

Forecasters at the National Hurricane Center expect it turn back to the west-northwest Thursday, with a slight increase in forward speed until it dissipates Friday.

The maximum sustained winds are near 70 mph. Dolly is expected to continue weakening as it moves farther inland. It may become a tropical depression by late Thursday.

Local officials' greatest fear -- that the levees holding back the Rio Grande would fail and cause massive flooding -- eased when Dolly meandered 35 miles north of the U.S.-Mexico border just before coming ashore Wednesday afternoon on South Padre Island as a Category 2 storm. About two hours later, Dolly's winds slowed to 95 mph, and the storm was downgraded to a Category 1.

The storm has forced thousands of people on both sides of the Texas-Mexico border into shelters.

Heavy rains and high winds from the storm collapsed an apartment roof, blown over signs and cut power to thousands of customers.

Most of the damage was on South Padre Island. Numerous roofs were ripped off and windows were smashed. The roadways and yards were strewn with trees, fences, power poles and fallen streetlights. Business signs rolled around the streets like tumbleweeds.

Authorities also said a 17-year-old boy fell from a seventh-story balcony on South Padre Island. They said he broke his hip, fractured a leg and hurt his head.

Thousands are reported without power in three counties, as well as South Padre Island.