Hurricane Dorian strengthened to an “extremely dangerous” Category 4 storm with maximum sustained winds at 145 miles per hour, the National Hurricane Center (NHC) announced this morning. That raised fears that Dorian could become the most powerful hurricane to hit Florida’s east coast in nearly 30 years. There is a possibility that Dorian could reach category 5, the strongest level for a hurricane.

As of 5 a.m. eastern yesterday, Dorian was about 305 miles east of the northwestern Bahamas and 470 miles east of West Palm Beach, Fla. It was moving west-northwest at 12 mph.

Late yesterday, the NHC’s new projected track showed Dorian making landfall near Fort Pierce then running along the coastline as it moved north.

But forecasters cautioned that the storm’s track was still highly uncertain and even a small deviation could put Dorian offshore or well inland.

“It is imperative that all Floridians and their families take Hurricane Dorian seriously,” Gov. Ron DeSantis said in a statement on Friday night. “The time to prepare diminishes by the hour, particularly because we are still uncertain of where it will make landfall. Everyone should have seven days of food, water and medicine in preparation for this storm. Additionally, all residents need to be prepared to evacuate, should that be required.”

However, authorities have held off on ordering mass evacuations, due to the uncertainty surrounding the storm’s ultimate path.

“Sometimes if you evacuate too soon, you may evacuate into the path of the storm if it changes,” DeSantis said.

Forecasters have warned that coastal areas could see 6 to 12 inches of rain, with up to 18 inches possible in isolated areas. That amount of rainfall “may cause life-threatening flash floods,” the NHC warned. Federal Emergency Management Agency (FEMA) official Jeff Byard said Dorian is likely to “create a lot of havoc” for roads, power and other infrastructure.

Also imperiled were the Bahamas, where canned food and bottled water were disappearing quickly and the sound of hammering echoed across the islands as people boarded up their homes. Dorian was expected to hit by Sunday with the potential for a life-threatening storm surge that could raise water levels as much as 10 to 15 feet above normal.

At Kennedy Space Center in Cape Canaveral, NASA moved a 380-foot-high mobile launch platform to the safety of the colossal Vehicle Assembly Building, built to withstand 125 mph wind. The launcher is for the mega-rocket that NASA is developing to take astronauts to the moon.

The hurricane season typically peaks between mid-August and late October. One of the most powerful storms ever to hit the U.S. was on Labor Day 1935. The unnamed Category 5 hurricane crashed ashore along Florida’s Gulf Coast on Sept. 2. It was blamed for over 400 deaths.