A powerful, slow-moving nor'easter is battering the East Coast this week in what forecasters are calling a rare occurrence for late September, threatening coastal flooding, high winds and heavy rain for tens of millions of people from North Carolina to Massachusetts.

The storm has already knocked out power to thousands of homes in Virginia Beach and northeastern North Carolina, where Dominion Energy reported outages peaking near 8,000 customers across Hampton Roads as winds toppled tree limbs onto power lines. Coastal flooding, tidal surge and beach erosion have hit the Virginia Beach-to-Norfolk area over multiple high-tide cycles this week, with officials warning that could worsen through the weekend.

Meteorologists say moderate to major coastal flooding is likely from North Carolina to Nantucket, Massachusetts, with 1 to 3 feet of water above normal high tide expected in the hardest-hit spots. Wind gusts of 50 to 60 mph are forecast to continue battering the coastline, and NBC News reports the heaviest rain — 2 to 3 inches or more — is targeting Rhode Island and eastern Massachusetts, with waves building to as high as 22 feet off New England.

Boston braces for the peak

The storm's center is expected to intensify as it slides north, with the worst conditions for New England arriving Friday evening into Saturday. Boston officials issued a coastal storm warning running from Friday through Sunday, forecasting 2 to 4 inches of rain, damaging winds and coastal flooding and erosion in low-lying neighborhoods.

"NOR'EASTERS AREN'T NEW FOR NEW ENGLAND, BUT NOT USUALLY IN SEPTEMBER, SO WE'RE TAKING EXTRA PREPARATIONS," — Boston Mayor Michelle Wu

The city canceled its Zero Waste Drop-Off Day, deployed extra water and sewer crews for round-the-clock operations, opened public libraries as storm shelters, and activated 24/7 emergency shelters with amnesty provisions for homeless residents. Emergency Management Director Brooke Amendola urged people in coastal and low-lying areas to prepare immediately, while Chief Climate Officer Brian Swett noted the city is "growing more vulnerable to severe weather and coastal flooding every year" amid rising seas.

The Boston Globe reports that a high wind warning covers the entire Massachusetts and Rhode Island coastline, with gusts strong enough to threaten fully leafed trees still standing from summer, raising the risk of widespread outages. Major League Baseball games in Boston and New York have already been rescheduled around the storm, and New York City issued a travel advisory running from Friday afternoon through Sunday.

Emergency officials up and down the coast are urging residents to avoid unnecessary travel during peak conditions, move vehicles out of flood-prone areas, and report downed trees or flooding to local 311 or emergency lines. Forecasters say conditions should gradually improve by Sunday as the storm pulls away from the coast, though a full moon Saturday night could intensify high tides and add to flooding risk in the interim.