Hurricane Nicole has made landfall in Florida, marking the second major storm to batter the state in recent months.
It initially struck the east coast as Category 1 hurricane, gathering strength after battering the Bahamas.
It was downgraded to a tropical storm by the National Hurricane Centre, which warned of dangerous storm surge and widespread heavy rains.
Wind gusts of up to 65 miles per hour were reported as it churned towards land. Nearly 40,000 people are without power in Brevard County alone, according to local meteorologists.
Around 18 million people were under NHC-issued warnings ahead of the storm's arrival, and 45 of 67 Florida counties in a state of emergency.
Nicole is estimated to incur more than $2 billion in damages and cause havoc across a large stretch of the US, with warnings in place up to South Carolina.
Storm Nicole Interactive Tracker
Florida is still reeling from the aftermath of Hurricane Ian, which killed more than 100 people and caused catastrophic damage in September. The state rarely sees November hurricanes - with only two such storms since records began.
"Dozens upon dozens" of oceanfront buildings are at "imminent" risk of collapse after being damaged by Hurricane Ian, Florida officials have said, an alarming prospect in a state which saw almost 100 people killed in last year's Surfside condominium collapse.
Mandatory evacuation orders have been issued in several low-lying areas, which include former President Donald Trump's Mar-a-Lago resort. Airports and theme parks were also closed on Wednesday as authorities braced for extreme conditions.
'Statewide impact'
The storm's impact will be felt statewide, said Florida's division of emergency management.
Residents should expect coastal flooding, rip currents, tornadoes and beach erosion, it added.
State officials opened 15 emergency shelters across the region, activated 600 National Guard troops and placed 1,600 utility workers on standby to restore power knocked out by the storm.
More than a dozen school districts were closed on Wednesday and more than 20 school districts across the state were scheduled to be shuttered on Thursday.
On Monday, Florida Governor Ron DeSantis issued a state of emergency for 34 east coast counties, saying it was “in an abundance of caution” so that local residents and businesses could prepare.
“While this storm does not, at this time, appear that it will become much stronger, I urge all Floridians to be prepared and to listen to announcements from local emergency management officials,” Mr DeSantis said in a statement.
Nicole is the 14th named storm of the 2022 Atlantic hurricane season, AP reported, matching the long-term average but short of the 19 to 21 tropical systems that researchers had been expecting this year.
Hurricane Ian caused an estimated $71 billion worth of damage when it struck Florida in late September.
President Joe Biden visited the state in the aftermath of the storm.
"There's a long road before us, rebuilding entire communities from the ground up," he said in a joint press conference with Governor DeSantis.
“I want the people of Florida to know you have my commitment and America's commitment that we're not going to leave. We're going to see you through this entire process," he added.
