Pensacola, Fla. ? Hurricane Dennis dealt a glancing blow to the Florida Keys on Saturday, knocking out power and leaving streets flooded with seaweed as it roared toward the storm-weary Gulf Coast, where nearly 1.4 million people were under evacuation orders.

The hurricane, blamed for at least 20 deaths in Haiti and Cuba, carried a threat of more than a half-foot of rain plus waves and storm surge that could be more than a story high when it makes landfall today somewhere along the coast of the Florida Panhandle, Alabama or Mississippi.

Dennis had grown to a Category 4 storm with 150 mph sustained wind early Friday, but it weakened when it crossed Cuba. It regained strength Saturday, and by afternoon it was back up to Category 2 with top sustained wind of 100 mph. National Hurricane Center forecasters said Dennis could strengthen into a Category 3 by landfall.

Dennis largely spared the Florida Keys as the eye passed west of the islands, but more than 211,000 homes and businesses lost power Saturday across the southern tip of Florida, including the entire city of Key West.

In Alabama, about 500,000 people were under evacuation orders, as were 700,000 in Florida and 190,000 in Mississippi. Florida Gov. Jeb Bush and Alabama Gov. Bob Riley urged residents to evacuate if they were told to do so.

Traffic doubled on some Mississippi highways as people fled inland from the coasts of Florida, Alabama and Louisiana. Alabama officials turned Interstate 65 into a one-way route north from the coast to Montgomery.

However, confident that the hurricane would make landfall farther east, officials in New Orleans told nearly half a million residents they could stay home. A voluntary evacuation was lifted for suburban Jefferson Parish, including the barrier island town of Grand Isle.

Many Gulf residents were still patching up roofs on their homes or living in government trailers because of damage caused by Hurricane Ivan just 10 months ago. For them, Dennis meant another tense weekend of long lines for gas and searching for generators and plywood.

“I’m tired of all this packing up,” said Melba Turner, 70, of Fort Walton Beach. “We look like the Beverly Hillbillies when we get all packed up and leave. I’d rather stay. We’re getting too old for all this fussing.”