HOUSTON — Hurricane Ike lashed the Texas coast Friday night with 110-mph winds as it churned toward Houston and threatened to devastate Galveston and other coastal towns with a wall of seawater 20 feet high.

By late Friday, more than a million Texans had left their homes for safer places inland, but tens of thousands decided to tough it out, and the authorities feared that those people had put their lives at risk. Officials in Galveston estimated that 40 percent of the city’s 57,000 residents had ignored an order to evacuate.

As many as 100,000 homes could be inundated by the wall of water expected to hit the coast, federal officials warned, and millions of people could be left without electricity.

“The size, strength and current path of the storm have the potential to produce catastrophic — let me repeat that — catastrophic effects and to threaten the lives and safety of citizens along the Texas coast and the western part of Louisiana,” Homeland Security Secretary Michael Chertoff said.

Forecasters said the giant storm — nearly 600 miles wide — would send water surging up Galveston Bay and into the Houston Ship Channel, the nation’s second-busiest port.

It was also expected to swamp neighborhoods along the seven bayous that thread through Houston.

Long before it was to come ashore, Hurricane Ike caused flooding all along the coast. It shut down 17 oil refineries, endangered a freighter at sea and destroyed a pier in Galveston.

“This is probably the biggest storm to hit the Texas coast in my lifetime, and I’m not a young bird,” Texas Gov. Rick Perry, 58, told KTRH radio.

Emergency officials said that there were sporadic house fires throughout Galveston on Friday mostly traced to transformers. The 61st Street pier was washed away, and several buildings lining the seawall had partly collapsed.

Galveston was mostly without power Friday night. Most of the buildings in downtown were flooded, as was the western part of the island. About five blocks inland from the seawall, streets were so submerged by 9 p.m. that the water had reached stop signs. Firefighters picked up more than 300 people who were wading through the streets after being forced from their homes.

One hurricane expert, Jeff Masters, warned that the storm “stands poised to become one of the most damaging hurricanes of all time” because of its vast size.

Some stranded

Officials said they were particularly worried about people in coastal towns who ignored evacuation orders. On the Bolivar Peninsula, a spit of land on the east side of Houston at the mouth of Galveston Bay, the sudden rush of seawater caught at least 200 people off guard, covering the only road. The Coast Guard rescued 96 people with helicopters but had to leave 100 behind after winds grew too strong to fly, the Coast Guard said.

Masters, who runs the Weather Underground Web site, said Hurricane Ike could end up being much larger and more powerful than Hurricane Katrina, which ravaged New Orleans in 2005. He also predicted that it would cause “the largest and longest-lived power outage in Texas history.”

The eye of the storm was forecast to make landfall after midnight just southwest of Galveston and to push a storm surge of 15 to 20 feet over the island’s seawall, up into Galveston Bay and up the Houston Ship Channel, a nightmare scenario for the nation’s fourth-largest metropolis and its oil industry.

President Bush, speaking in Oklahoma City, said he was “deeply concerned” about the potential effects of the hurricane.

“The federal government will not only help with the pre-storm strategy,” he said, “but once this storm passes, we’ll be working with state and local authorities to help people recover as quickly as possible.”

The winds at the eye wall of the hurricane were about 110 mph, but it was the storm’s size that made it dangerous, causing 50-foot waves as it swept over the shallow Gulf waters.

Federal forecasters said the storm’s size meant it would produce high storm surges along the coast in western Louisiana and eastern Texas, as well as 5 to 10 inches of rain.

Officials in Houston urged most residents who do not live in coastal regions near the bay to remain in their homes.

The decision was a calculated risk. Local officials hope to avoid the chaos and clogged highways that occurred after residents were ordered to evacuate Houston when Hurricane Rita threatened the city in 2005.

The oil refineries

The storm shuttered at least 17 refineries in the Houston area, including those owned by ExxonMobil, Valero, BP, ConocoPhillips and Shell, which alone handle about 13 percent of the nation’s oil processing needs.

Energy experts said it would take at least a week for the refineries to begin anything close to normal operations, and flood damage or power failures could mean further delays. Damage to the Port of Houston could disrupt oil imports and tighten oil and gasoline supplies further.

Gasoline prices have surged around the country, especially in the Gulf region, where prices for regular unleaded at some stations climbed by 20 cents or more in the last day or two.

The Coast Guard reported that the situation at sea had become so dangerous that it could not evacuate 36 men adrift on a 584-foot freighter, the Antalina, registered in Cyprus, which was about 90 miles off the Galveston coast.

The ship was in the direct path of Hurricane Ike. The crew, which had lost power about 4 a.m. Friday, will have to tough it out until after the storm, the Coast Guard said.

Mayor Bill White of Houston said the police and fire departments were gearing up to rescue people who were stranded by floods.

The federal government has moved about 3,500 rescue workers into place just outside the storm’s expected path, along with about 2.4 million quarts of water, 2 million military meals and 203 generators to power hospitals and other critical government buildings, said Debbie Wing, a spokeswoman for the Federal Emergency Management Agency.

The state has also sent in 7,500 national guardsmen.