MIAMI (NYTIMES)- After cutting a deadly path through the Caribbean this week, Hurricane Matthew crept ominously toward Florida on Wednesday as tourists and locals rushed to safety before a storm that officials said could deliver "devastating" blows along the East Coast beginning as early as Thursday (Oct 6).

Forecasters said the hurricane, which had sustained winds of about 115 mph, could strengthen from a Category 3 to a Category 4 storm as it approached Florida, where hurricane conditions were expected to begin taking hold just north of Miami late Thursday.

The governor's office said that more than 1.5 million people were in evacuation zones in Florida. Mandatory evacuations for the barrier islands in the hurricane warning areas were to begin Thursday at 8 am

States of emergency were in effect Wednesday in Florida, Georgia, North Carolina and South Carolina - and residents scrambled to prepare for the storm, all the while guessing and second-guessing where it might make landfall in the United States, if it landed at all: The storm's wobbling path kept government officials and even meteorologists struggling to predict its next move.

But authorities said that even if it remained offshore, the pounding rain and lacerating winds, which extended up to 175 miles from the eye, could cause mayhem.

In coastal communities like Fort Pierce, Florida, few were taking chances. At Chuck's Seafood Restaurant, an easygoing place known for its fried shrimp and sunset happy hours, workers were busy fastening hurricane shutters and readying generators Wednesday afternoon. The restaurant was heavily damaged in 2004 when two hurricanes assaulted the area in rapid succession. The memories, and the lessons, were still fresh.

"Most people, I think, are taking it pretty seriously because we don't know where it's going to fall," said Wyndie Willis, the manager. "At this point, all you do is prepare for it, and hopefully it doesn't hit anybody."

Forecasters remained unsure whether the storm would become the first major hurricane to make landfall in Florida since Hurricane Wilma in 2005 or would lash the coastline while remaining offshore.

Hurricane Wilma reached Category 5 strength on the Saffir-Simpson scale and did tremendous damage in Mexico. And although it was a Category 3 storm by the time it hit Florida, it still left US$21 billion in damage to the state in its wake.

"Regardless of if there's a direct hit or not, the impacts will be devastating," Gov. Rick Scott of Florida said. "I cannot emphasise enough that everyone in our state must prepare now for a direct hit."

The American Red Cross was planning to open nearly 100 shelters in Florida, and Scott agreed to suspend highway tolls in affected areas. As oceanfront hotels and restaurants closed, people hustled their lawn furniture and planters inside and shielded windows and glass doors with hurricane shutters.

"I'm kind of freaking out," said Carolina Silva, 20, who arrived here from Venezuela last year, as she shopped in Miami for storm provisions. "I'm scared something will happen to my house and we won't have anywhere to go."

Lines at petrol stations stretched far beyond the pumps, and anxious shoppers raided supermarkets for bread and canned goods. The anxiety stretched inland, where a Target in Orlando had been emptied of flashlights and water by noon.

President Barack Obama, who visited the Federal Emergency Management Agency's headquarters in Washington on Wednesday, said people should be prepared to flee their homes with little warning.

"We anticipate that not only is there still a chance that the core of the storm strikes Florida and some of the states further north, but even if you don't get the full force of the hurricane, we are still going to be seeing tropical force winds, the potential for a storm surge, and all of that could have a devastating effect," he said.

Along the East Coast, officials were bracing for days of trouble, including possible flooding. Researchers predicted that more than 8 million people could lose electricity, and forecasters Wednesday raised the possibility that the storm could curve back toward Florida after its initial strike.

Residents were equally on edge in South Carolina, a state still haunted by the memory of Hurricane Hugo, which ravaged Charleston and its historic district in 1989. At a news conference Wednesday morning in West Columbia, Gov. Nikki R. Haley said she had ordered about 250,000 people near the coast to evacuate beginning Wednesday afternoon.

The worst of the storm will probably reach the South Carolina coast this weekend, and Haley said another 250,000 people might have evacuated by then.

Haley's warnings about the weather spurred frenzied shopping and forced people to make quick, and sometimes complicated, decisions about whether to stay or go. In suburban North Charleston, a Wal-Mart was a predictable hive of commerce. People bought their necessities by the case. By 1:30pm the water was almost all gone, and the supply of diapers was running low.

Maynard Terry, 40, had five cases of bottled water in a cart, along with his girlfriend's eight-year-old daughter. Terry said they could not leave town, because his girlfriend's grandmother refused.

"She's in poor health and she's stubborn and she don't want to go," he said. He smiled and said they were going to make the most of it. "We're just going to chill," he said. "It's going to be family time."

Nearby, hundreds of yellow public school buses snaked around the massive complex housing the North Charleston Coliseum and the Charleston Area Convention Center, preparing to haul the elderly, the poor and those without cars away from the Lowcountry before Hurricane Matthew struck.

The buses were to take the evacuees to Greenville, South Carolina, more than 230 miles to the northwest.

Jacqueline Holmes and her husband, Andrew, both 54, came to the improvised bus depot with bags full of chips, water, deodorant and flushable wipes.

She recalled Hurricane Hugo's power.

"It was the most terriblest thing I ever saw," she said.

In Miami, the cautionary notes, even for those who did not experience it, were of Hurricane Andrew, the Category 5 storm that hit in 1992.

Brenda Leto, a Miami native, scoured the shelves at a grocery not far from the southern portion of the bay, with her teenage son and his friend. The teenagers won the day: There were bottles of Gatorade, a jar of Nutella, cases of Pepsi and Mountain Dew and chocolate Krave cereal.

Leto had bad memories from 1992.

"Storms decide to change at the last second," she said.