WASHINGTON (AFP)

Hurricane Erin's furthest bands began brushing the outer banks of North Carolina's coast on Wednesday, where the Category 2 storm triggered mandatory evacuation orders, and officials warned summer beachgoers along the US East Coast of life-threatening surf and rip currents in the coming days.

Landfall isn't expected for Erin -- welcome news for the southern US state still reeling from last year's deadly Hurricane Helene -- but North Carolina officials declared an emergency Tuesday as Erin's predicted impacts began taking shape.

Portions of coastal North Carolina and Virginia were under tropical storm warnings, according to officials at the National Hurricane Centre (NHC).

"Swells generated by Erin will affect the Bahamas, Bermuda, the east coast of the United States and Atlantic Canada during the next several days," NHC said, adding that "Erin is a large hurricane."

As of Wednesday afternoon, Erin was churning northward some 245 miles (395 kilometres) southeast of North Carolina, packing maximum sustained winds of 110 mph (175 kph), the NHC said -- with the possibility it could still restrengthen to a major hurricane.

Its unusually large size means tropical storm-force winds extend hundreds of miles from its centre, earning it the moniker "Enormous Erin" by hurricane specialist Michael Lowry, who wrote on Substack that the United States was fortunate to be spared a direct hit.

Mandatory evacuation orders were in effect for Ocracoke and Hatteras Islands in North Carolina.

North Carolina Governor Josh Stein urged residents to store enough food, water and supplies to last up to five days -- and to safeguard important documents like insurance policies.

"We have already pre-positioned three swift water rescue teams and 200 National Guard troops to various locations on the coast, along with boats, high clearance vehicles and aircraft," he added.