MIAMI — A ferocious Hurricane Wilma yesterday made a slow-motion assault on the Mexican tourist havens of Cozumel and Cancún. The storm's grinding passage through the Yucatán Peninsula — it was moving no faster than a jogger — again delayed its projected arrival in Florida.

In Cancún, roofs flew away in the 140 mph wind and tin siding sliced the air. Windows shattered and falling trees crushed cars. Ninety percent of the city lost power even before Wilma's core reached land.

Wilma had been expected to strike somewhere on the west coast of Florida this weekend. Its erratic movement frustrated residents worried about what would be the eighth hurricane to hit or pass near the state since August 2004.

Said Max Mayfield, director of the National Hurricane Center in west Miami-Dade County: "By the time this gets here, I could be retired."

Still, Wilma's outermost rain drizzled and occasionally poured on South Florida throughout the day, and the weather there is expected to slowly deteriorate over the weekend.

Wilma will likely linger over the Yucatán for a few days, which should weaken the hurricane's top sustained winds to 130 mph or lower. It could hit Florida on Monday.

"That would obviously be terrible news for Mexico, but for the United States' interests it means that we'll have a weaker hurricane coming out into the Gulf of Mexico, and it will be slower in getting here," Mayfield said.

In the Yucatán, the waiting for Wilma was over.

The hurricane moved with tormenting slowness — a forward speed of 5 mph, prolonging a Yucatán agony that could persist until tonight. Forty inches of rain were possible in parts of the Yucatán and western Cuba. Forecasters also warned of 11-foot coastal storm surges.

"We're really taking a beating," said Israel Reyes de la Cruz, a security guard at the La Voz de Mexico newspaper in Cancún. "There's glass everywhere, sheer glass. It looks like everything is getting destroyed."

Wilma's Category 4 core crashed into the island of Cozumel, then passed close to the high-rise tourist center of Cancún, a seaside city lined with hotels and restaurants.

Thousands of residents and stranded tourists sought safety in public shelters and hotel ballrooms. Others were bused to distant cities.

Felix Gonzalez Canto, the governor of Quintana Roo state, said some buildings on Cozumel Island that had been reinforced against hurricane-force winds had collapsed.

But as of last night there were no reports of deaths there, and the governor expressed confidence that his state would be able to withstand the storm.

Wilma already has killed 13 people in Haiti and Jamaica.

In Cuba, 367,000 people were evacuated and extremely heavy rain fell in the western and central parts of the island.

Forecasters said Wilma was trapped between two high-pressure systems, causing its slow passage over the Yucatán. The lengthy stay over land will sap its strength, they said, but not destroy it because the peninsula — with its lagoons, lakes and mangroves — is flat and fairly friendly to hurricanes.

As a consequence, forecasters slowed their projection of Wilma's voyage to Florida. But it will arrive, they said.

"Everything we see says this is still coming," Mayfield said.

The Bush administration said the government was better prepared to deal with any devastation from a new storm because of lessons from the response to Hurricane Katrina.

Frances Fragos Townsend, the Homeland Security adviser to the president who is leading an internal White House inquiry into how the administration handled Katrina's aftermath, said preliminary findings showed a severe breakdown in communications and a lack of information flowing back to Washington from the scene.

Despite years of simulations and planning for a disaster like Katrina, she said, the government was caught off-guard.

"The sense of everyone who had been involved at that time was that we were appropriately positioned and we had the mechanisms in place," Townsend said. "It turned out we were all wrong. We had not adequately anticipated."

In preparing for Hurricane Wilma, Townsend said, the government has dispatched more officials and communications equipment to Florida than during previous hurricanes. She said the U.S. Northern Command had positioned planners in Washington to deploy the military if needed.

The White House, eager to show it was aggressively preparing for Wilma, staged a briefing for Townsend to discuss the administration's study of what went wrong in responding to Katrina.

Congressional committees also have launched inquiries, calling witnesses from the Federal Emergency Management Agency, the Department of Homeland Security and an array of local authorities.

Townsend said the inquiry would be completed by January, allowing time for any legislative action before another hurricane season arrives.

Material on FEMA is from The Chicago Tribune. Additional information is from Los Angeles Times and The Associated Press.