WILMINGTON, N.C.  — The big slosh has begun, and the consequences could be disastrous.

Hurricane Florence’s leading edge battered the Carolina coast Thursday, bending trees and shooting frothy sea water over streets on the Outer Banks, as the hulking storm closed in with 100 mph (155 kph) winds for a drenching siege that could last all weekend.

Forecasters said conditions will only get more lethal as the storm pushes ashore early Friday near the North Carolina-South Carolina line and makes its way slowly inland. Its surge could cover all but a sliver of the Carolina coast under as much as 11 feet of ocean water, and days of downpours could unload more than 3 feet of rain, touching off severe flooding.

Florence’s winds weakened as it drew closer to land, dropping from a peak of 140 mph (225 kph) earlier in the week, and the hurricane was downgraded from a terrifying Category 4 to a 2.

But North Carolina Gov. Roy Cooper warned: “Don’t relax, don’t get complacent. Stay on guard. This is a powerful storm that can kill. Today the threat becomes a reality.”

Forecasters said that given the storm’s size and sluggish track, it could cause epic damage akin to what the Houston area saw during Hurricane Harvey just over a year ago, with floodwaters swamping homes and businesses and washing over industrial waste sites and hog-manure ponds.

“It truly is really about the whole size of this storm,” National Hurricane Center Director Ken Graham said. “The larger and the slower the storm is, the greater the threat and the impact — and we have that.”

The hurricane was seen as a major test for the Federal Emergency Management Agency, which was heavily criticized as sluggish and unprepared for Hurricane Maria in Puerto Rico last year.

As Florence drew near, President Donald Trump tweeted that FEMA and first responders are “supplied and ready,” and he disputed the official conclusion that nearly 3,000 people died in Puerto Rico, claiming the figure was a Democratic plot to make him look bad.

Schools and businesses closed as far south as Georgia, airlines canceled about 1,200 flights and counting, and coastal towns in the Carolinas were largely emptied out.

Around midday, Spanish moss blew sideways in the trees as the winds increased in Wilmington, and floating docks bounced atop swells at Morehead City. Some of the few people still left in Nags Head on the Outer Banks took photos of angry waves topped with white froth. By early afternoon, utilities reported about 12,000 homes and businesses had lost power.

Wilmington resident Julie Terrell was plenty concerned after walking to breakfast past a row of shops fortified with boards, sandbags and hurricane shutters.

“On a scale of 1 to 10, I’m probably a 7” in terms of worry, she said. “Because it’s Mother Nature. You can’t predict.”

Forecasters’ European climate model is predicting 2 trillion to 11 trillion gallons of rain will fall on North Carolina over the next week, according to meteorologist Ryan Maue of weathermodels.com. That’s enough water to fill the Empire State Building nearly 40,000 times.