SAN JUAN, Puerto Rico >> Tropical Storm Dorian made a last-minute shift in its path today, threatening Puerto Rico with a direct hit as forecasters said it could reach near-hurricane strength in its approach to the U.S. territory.

The storm is expected to pass over or near western and central Puerto Rico on Wednesday as authorities warned of landslides, widespread flooding and power outages. President Donald Trump declared an emergency tonight and ordered federal assistance for local authorities.

“Practically the entire island will be under sustained tropical storm force winds,” said Roberto García, director of U.S. National Weather Service San Juan, during a press conference late today.

However, he said the forecast could change overnight, adding that late shifts occur with storms such as Dorian that do not have a well-defined center.

Dorian was located about 300 miles (480 kilometers) southeast of Ponce, Puerto Rico, tonight. The U.S. National Hurricane Center said it had maximum sustained winds of 50 mph (85 kph) and was forecast to strengthen during the next 24 hours as it moves west-northwest at 13 mph (20 kph). The storm is expected to dump 4 to 6 inches (10 to 15 centimeters) of rain with isolated amounts of 8 inches (20 centimeters).

The change in the storm’s course concerned many across the U.S. territory, where some 30,000 homes still have blue tarps as roofs nearly two years after Hurricane Maria. The island’s 3.2 million inhabitants still depend on a shaky power grid that has remained prone to outages since it was destroyed by the Category 4 storm.

Jorge Ortiz, a 50-year-old construction worker, was taking no chances. Wiping sweat from his brow, Ortiz climbed up a shaky ladder under a punishing morning sun and tied down pieces of zinc that now serve as his roof because Maria ripped the second floor off his house when it hit on Sept. 20, 2017.

He was forced to rebuild everything himself and finished just three months ago with no assistance from the local or federal government.

“They told me I didn’t qualify because it was a total loss,” he said, shaking his head as he added that he was wary. “I’m worried that despite all this sacrifice, I’ll lose it again.”

The U.S. National Hurricane Center issued a hurricane watch for Puerto Rico and a tropical storm warning for Puerto Rico, Vieques, Culebra and the U.S. Virgin Islands. A tropical storm watch was in force for the Dominican Republic from Samaná to Puerto Plata.

Dorian already caused power outages and downed trees in Barbados and St. Lucia, and a still-uncertain long-term track showed the storm near Florida over the weekend.

Although top government officials in Puerto Rico said they were prepared for the storm and had sufficient equipment, a couple of mayors, including those in the western region, said they did not have enough generators or shelters that were properly set up.

Jesús Laracuente, a 52-year-old construction worker who lives in the impoverished neighborhood of Las Monjas in the capital of San Juan, also had doubts about government preparations.

“The people here are prepared. We already learned our lesson,” he said, referring to Maria. “What despairs us is knowing that the slightest breeze will leave us without power. It’s the government that fails us.”

José Ortiz, executive director of Puerto Rico’s Electric Power Authority, acknowledged that the distribution system still has weak areas and could “suffer” under winds of 50 to 60 mph. However, he stressed the agency has the needed inventory, including more than 120,000 lights, 23,000 poles and 7,400 transformers.

But Freddyson Martínez, vice president of a power workers’ union, told The Associated Press that while the electric grid has improved in some areas, he worries about a lack of power line workers and post-Maria patches which feature lines affixed to palm trees.

“Those are problems that are still being corrected to this day,” he said. “These are the realities we have to face with this storm.”

The island’s transportation secretary acknowledged that crews are still rebuilding roads damaged or blocked by Maria, more than 1,000 of which remain blocked by that storm’s landslides.

Puerto Rico Gov. Wanda Vázquez urged those living in flood-prone areas or under a blue tarp to move into one of the island’s 360 shelters tonight. Housing Secretary Fernando Gil has said some 9,000 to 13,000 homes with blue tarp roofs are located in the region that Dorian is expected to affect the most.

Officials also said public schools and government offices would remain closed through at least Thursday.

“We learned our lesson quite well after Maria,” Vázquez said. “We are going to be much better prepared.”

Dorian was expected to move near the Turks and Caicos Islands and southeastern Bahamas on Thursday night or Friday.

Meanwhile, Tropical Storm Erin formed well off the U.S. East Coast tonight. It was located about 430 miles (691 kilometers) west of Bermuda and 300 miles (482 kilometers) southeast of Cape Hatteras, North Carolina, and was moving northwest at 2 mph (3 kph) today with maximum sustained winds of 40 mph (64 kph).