Larger than the state of California, Hurricane Earl prepared to take a swipe at the Eastern Seaboard on Thursday as residents scrambled to ready themselves ahead of its arrival.

Hurricane warnings and watches stretched from North Carolina to Delaware, and covered parts of Massachusetts.

President Barack Obama signed a disaster declaration for North Carolina Wednesday evening. The action authorizes the Department of Homeland Security and the Federal Emergency Management Agency to coordinate relief efforts, and also makes federal funds available to states. Maryland’s governor issued an emergency declaration earlier in the day.

The monster storm is forecast to pass close to North Carolina’s Outer Banks on Thursday night, the National Hurricane Center said. It is expected to take aim at southeastern New England on Friday night. The storm’s track shifted slightly to the west, closer to North Carolina’s Cape Hatteras. The National Hurricane Center has posted storm watches and warnings for areas as far north as Maine.

Officials in Dare County, North Carolina, issued mandatory evacuation orders Thursday for visitors to the coastal county, including the Outer Banks. The mandatory evacuation extended to residents in some areas, including the town of South Nags Head and Hatteras Island. Dare County schools and courts were closed Thursday and will be closed Friday.

As of 8 a.m., the center of Earl was located about 355 miles (570 kilometers) south of Cape Hatteras, North Carolina, and about 820 miles (1,320 kilometers) south-southwest of Nantucket, Massachusetts. It was heading north-northwest at about 18 mph (30 kph).

Earl is a Category 4 hurricane with maximum sustained winds of near 145 mph (230 kph) and gusts up to 175 mph. It is also a large storm, meaning effects will be widely felt even if it does not make a direct hit.

Earl covers about 166,000 square miles — larger than California, which covers just under 160,000 square miles. The storm’s outflow, or the clouds associated with it, could stretch from one end of the state of Texas to the other, said CNN meteorologist Reynolds Wolf.

The North Carolina coast should begin experiencing tropical-storm-force winds of at least 39 mph by Thursday afternoon, forecasters said, with hurricane-force winds of at least 74 mph arriving later in the day.

Rip currents and stormy seas were reported all the way up the East Coast, from Florida to Maine.

Earl will make its closest pass to New Jersey on Friday afternoon as a Category 2 hurricane, Morris said. It is expected to make its closest pass to Cape Cod, Massachusetts, on Friday night as a Category 1 hurricane.

(Read More: CNN)