Floodwaters surged into Galveston Island neighborhoods Friday morning with the center of Hurricane Ike still more than 200 miles from landfall.

On the Bolivar Peninsula, northeast of Galveston, the Coast Guard was rescuing stranded motorists by helicopter.

A U.S. military official told CNN that Texas anticipates 37,000 people may need to be rescued.

Texas has asked for help, and the active-duty military has 42 search-and-rescue helicopters on standby, the official said.

On Galveston Island, waves washed for blocks inland, the beginning of a storm surge that forecasters warned could reach up to 22 feet and bring "certain death" to anyone who remained in Galveston Bay homes.

The weather service painted a vivid picture in its warning of the destruction it expects: a towering wall of water, possibly up to 22 feet high, crashing over the Galveston Bay shoreline as the brunt of Ike comes ashore. That wall of water could send floodwaters surging into Houston, more than 20 miles inland. Video Watch CNN meteorologists track Hurricane Ike »

"All neighborhoods ... and possibly entire coastal communities ... will be inundated during the peak storm tide," the weather service warned. "Persons not heeding evacuation orders in single family one- or two-story homes will face certain death."