HOUSTON — Hurricane Ike, a colossal storm nearly as big as Texas itself, began battering the coast Friday, threatening to obliterate waterfront towns and give the skyscrapers, refineries and docks of the nation's fourth-largest city their worst pounding in a generation.

As the storm closed in, it trapped 60 people who had to be rescued from the floodwaters by helicopter, sent towering waves smashing over the 17-foot Galveston seawall, breached levees in rural Louisiana, and tossed around a disabled 584-foot cargo ship in the Gulf of Mexico.

About a million people in low-lying coastal areas were ordered to get out well ahead of the storm. But authorities in three counties alone said roughly 90,000 of them refused, despite a warning from forecasters that those staying behind in Galveston faced "certain death."

"I believe in the man up there, God," said William Steally, a 75-year-old retiree who planned to ride out the storm in Galveston without his wife or sister-in-law. "I believe he will take care of me."

At about 600 miles across, the hurricane was one of the largest in recent memory, taking up almost the entire northern half of the Gulf of Mexico.

As of 5 p.m. EDT, Ike was centered about 135 miles southeast of Galveston, moving at 12 mph. It was a Category 2 storm, with winds of 105 mph, but was expected to strengthen to a Category 3, or at least 111 mph, by the time it hit land.

Forecasters predicted it would come ashore somewhere near Galveston late Friday or early Saturday and pass almost directly over Houston.

Because of the hurricane's size, the state's shallow coastal waters and its largely unprotected coastline, forecasters said the biggest threat would be flooding and storm surge, with Ike expected to hurl a wall of water two stories high — 20 to 25 feet — at the coastline.

To avoid highway gridlock, authorities instructed most of Houston's 2 million residents to just hunker down.

Still, authorities warned that the storm could travel up Galveston Bay and send a surge up the Houston Ship Channel and into the port of Houston, the nation's second-busiest port — a complex of docks, pipelines, depots and warehouses that receives automobiles, consumer products, industrial equipment and other cargo from around the world and ships out vast amounts of petrochemicals and agricultural products.

The oil and gas industry was also closely watching Ike because it was headed straight for the nation's biggest complex of refineries and petrochemical plants. Wholesale gasoline prices jumped to around $4.85 a gallon for fear of shortages.

The storm could also force water up the seven bayous that thread through Houston, swamping neighborhoods so flood-prone that they get inundated during ordinary rainstorms.

Bachir Annane, a scientist at the National Oceanic and Atmospheric Administration's Hurricane Research Division, said Ike's surge could be catastrophic, and like nothing the Texas coast has ever seen.

"Wind doesn't tell the whole story," Annane said. "It's the size that tells the story, and this is a giant."

Ike would be the first major hurricane to hit a U.S. metropolitan area since Katrina devastated New Orleans three years ago. For Houston, it would be the first major hurricane since Alicia in August 1983 came ashore on Galveston Island, killing 21 people and causing $2 billion in damage.

In southwestern Louisiana near Houma, Ike breached levees, threatening thousands of homes of fishermen, oil-field workers, farmers and others. Crews struggled to plug four breaches. "We've got a bad situation," said Windell Curole, levee manager for Terrebonne Parish.

Before the storm even arrived, rescue crews were being tapped. Because of high winds, the Air Force and Coast Guard aborted plans to send aircraft to the Gulf of Mexico in a daring attempt to rescue 22 crewmen adrift on a stalled freighter in rough seas 90 miles off Galveston.

And Coast Guard helicopter crews plucked 60 people from the town of High Island on the Bolivar Peninsula, a 32-mile spit just up the coast from Galveston, after rising waters covered the only road.

In Galveston, a working-class town of about 57,000, waves crashed over the 11-mile seawall built a century ago, after the Great Storm of 1900 killed 6,000 residents. That hurricane remains the nation's deadliest natural disaster.

The sight of the storm's fury frightened some people who initially intended to stay.

"We started seeing water come up on the streets, then we saw this. We just loaded up everything, got the pets. We're leaving," 33-year-old Tony Munoz said in Galveston. "I've been through storms before, but this is different."

While the beachfront is dotted with new condominiums and some elegant beach homes on stilts, most people live in older, one-story bungalows. The National Weather Service warned "widespread and devastating" damage was expected.

In Surfside Beach, a town of 800, the police chief asked one stubborn couple, David and Dondi Fields, to write their names and Social Security numbers on their forearms with a black marker in case something bad happened to them.

Dondi Fields, 50, wrote "I heart U" and "for my kids" on her arm. But the couple finally decided to leave. Police used an aluminum boat to reach them, and a National Guard truck carried them to safety.

In Freeport, Drew Ryder, 47, took no chances. He left his plywood-covered home, heading north with coolers filled with food.

"It's coming, so I'm going," he said. "It's not smart to be here."

Houston's streets were eerily quiet, emptied of the usual weekday traffic. Skyscrapers were darkened, and sandbags protected the lobby doors to some.

At the Flying Saucer Draught Emporium, a bartender secured plywood over windows as two dozen customers drank beer, ate burgers and watched scenes of Galveston on giant TV screens.

Andy Weeks, a retiree who serves as the homeowners association president in the eight-story building, spent the morning knocking on doors and reminding neighbors to bring their patio furniture and plants inside. The windows were bare of any plywood or other protection.

"It's pretty tough to get outside to board up your windows," said 64-year-old Weeks, who lives on the sixth floor.

Gloria Dulworth, who lives on the seventh of a high-rise apartment building, refused to let the storm dampen her plans to celebrate her 81st birthday.

"We're surrounded by glass, so I'm taking my crystal candlesticks down. It's been suggested that we roll the rugs away from the door," in case water seeps in. Other than that, said Dulworth, "I'm going to get some fresh veggies. I have cereal and canned milk. I anticipate being without air conditioning for a couple of weeks, but you can't do much."

Associated Press writers Kelley Shannon in Austin, Paul Weber and Regina L. Burns in Dallas, John Porretto, Andre Coe and Pauline Arrillaga in Houston, Diana Heidgerd in Dallas, and Allen G. Breed and video journalist Rich Matthews in Surfside Beach contributed to this report.