Northeast storm: At least 3 killed, over 600,000 without power

More than 600,000 customers were without power in seven Northeastern states on Tuesday morning as a powerful storm drenched the region.

The majority of the outages were in Maine, where about 429,000 customers were without power, followed by Massachusetts, where about 133,000 had lost power, according to poweroutage.us. Thousands of others in Connecticut, Rhode Island, New Hampshire, New Jersey and New York were without power, according to the site.

Residents across the region faced dangerous conditions on the roads due to heavy rain, flooding and strong winds. Up to 6 inches of rain was recorded in some areas.

At least three people died on Monday from the storm.

In Plymouth County, Massachusetts, an 89-year-old man was killed by a fallen tree that trapped him in a trailer, according to the Plymouth County District Attorney's Office.

In Windham, Maine, a man was struck and killed by a tree while he was on his roof trying to remove debris, Windham police said.

In upstate Greene County, New York, a driver died after their car was swept away in floodwaters, according to the Greene County Sheriff's Office.

A flood advisory was issued in New York City, where residents faced power outages, downed trees and flooded roads on Monday.

New York City Mayor Eric Adams issued a travel advisory, urging New Yorkers to stay off the roads and take mass transit.

High wind alerts were also issued from North Carolina to Maine.

Over 500 flights within, into or out of the U.S. have been canceled Monday. New York City's LaGuardia Airport and Boston Logan International Airport were the hardest hit.

In Essex County, New York, where a state of emergency was declared due to road flooding, several schools closed early. In Worcester County, Massachusetts, dangerous roads and a loss of power has prompted classes to be canceled for the Blackstone-Millville Regional School District.

By Monday afternoon, the rain stopped in New York City but was ongoing in New England.

On Monday evening, the biggest threat will be strong winds along the coast. Dangerous, hurricane-force winds are possible in northern Maine.

The storm brought rain to Florida and record-breaking flooding to South Carolina over the weekend.

More than 16 inches of rain fell between Charleston and Georgetown, South Carolina, flooding neighborhoods and stalling cars. A few areas received about 6 inches of rain in six hours.

Charleston measured its highest "non-tropical" tide on record.

ABC News' Ahmad Hemingway, Victoria Arancio and Kevin Shalvey contributed to this report.