More than 2.3 million customers are without power.
At least three people are dead after Hurricane Zeta slammed into the South, leaving a trail of destruction before turning toward the Northeast.
One person died in New Orleans and another in Biloxi, Mississippi.
In Acworth, Georgia, a man was killed when a large oak tree uprooted and fell through the corner of a mobile home, authorities said.
More than 2.3 million customers were without power Thursday morning across Louisiana, Mississippi, Alabama, Georgia, South Carolina and North Carolina.
Louisiana Gov. John Bel Edwards warned residents to not “go sightseeing” to inspect the damage.
“Zeta has left hazards like flooded roads, downed power lines and displaced wildlife in our communities that no one should take lightly,” he tweeted Thursday.
Zeta made landfall Wednesday as a Category 2 storm in Cocodrie, Louisiana, just south of New Orleans. Zeta is the strongest storm to hit the U.S. this late in the season since 1899.
Louisiana has been especially hit hard this hurricane season. Zeta is the fifth storm to hit the state.
Zeta has now moved into northern Alabama and Georgia.
Heavy rain and gusty winds from Zeta will move into the Northeast Thursday afternoon and evening, with flooding possible from Washington, D.C., to southern New England. Some of the worst flooding likely will be from Washington to central New Jersey.
Further north, the rain will begin to change to snow as cold air moves into northern New York and New England Thursday evening.
By Friday morning, the heaviest rain will be over, but whatever is left will be changing to snow very quickly from Pennsylvania into most of New York, Massachusetts and Connecticut.
Snowfall totals could reach up to 4 inches from upstate New York into Vermont, New Hampshire and the higher elevations of western Massachusetts and northern Connecticut.