Four people died after Hurricane Isaias made landfall early on Saturday near Destin, Florida, as about 670,000 residents across Florida, Alabama, Georgia and Mississippi remained without power while the storm weakened to a post-tropical cyclone.

Two of the deaths resulted from trees falling on homes. In Birmingham, Alabama, a tree crashed into a home, trapping two people; one fell through the floor and the second, pinned beneath the tree, was confirmed dead. In Escambia County, Florida, near Pensacola Beach, a woman was killed by a fallen tree. In Pensacola, a man died from generator fumes after running a generator indoors without proper ventilation; four other people in the home were hospitalised with carbon monoxide poisoning.

Outages across four states

About 420,000 customers in Florida, 190,000 in Alabama, 43,000 in Georgia and 17,000 in Mississippi had no power as of midday Saturday, according to tracking firm PowerOutage.us. Some 16,000 utility linemen had prepared to respond, Florida Governor Ron DeSantis said, adding that authorities had received no search and rescue requests shortly after landfall — a sign of limited impact — but warning that hazardous conditions remained.

The National Hurricane Center said storm surges, flash flooding, damaging winds and a tornado risk across parts of the US Southeast were expected to continue, with the tornado threat extending across the Florida Panhandle, Georgia and the Carolinas on Saturday.

How the storm unfolded

Isaias had reached Category 3 strength before weakening to a Category 2 hurricane as it approached the coast, making landfall with maximum sustained winds of around 105 mph. States of emergency were declared in parts of Alabama and Florida and across Georgia, with mandatory evacuation orders in force for some coastal areas of Alabama and northwest Florida.

The storm also disrupted US oil production in the Gulf of Mexico earlier in the week. Meanwhile, a separate Pacific storm, Rachel, was moving toward northern Baja California, leaving about 7,000 people without power in California. Officials expect power to return gradually over the coming days and urged residents to stay alert to flooding.