4 dead as Hurricane Isaias lashes US Southeast and moves inland

Deadly Hurricane Isaias has weakend overnight into a post-tropical cyclone but still contines to fuel storm surge and tornado threat in southeastern US as it charges inland across Alabama.

Isaias came ashore near Destin, a vacation spot in Florida, Friday night as a category 2 hurricane with winds of 105 miles per hour.

Nearly 900,000 customers suffered power outages in the first few hours after its landfall.

Officials reported at least four deaths linked to the storm, including two people killed by falling trees in Florida and Alabama.

Residents in Milton woke up to see roofs ripped off from a large section of an apartment complex after a harrowing night of downpours. Drone footage shows exposed furniture, personal belongings, insulation and other debris scattered in the rooms.

A woman spent the morning surveying the damage and moving roof shingles alongside her daughter.

Jayme Mitich, whose home was destroyed by Isais, said: "When the storm started to pick up, I could hear something going through the back that just didn't sound normal, like it sounded like a freight train."

"You know, I'm feelig a little bit displaced for sure, I'm feeling scared a little bit of the uncertainty of what's to come," Mitich said.

Recovery efforts have begun along the Gulf Coast while businesses and roads are reopening in affected areas.

But hazardous conditions remain.

Florida authorities warn the public over the weekend that flooding could still occur in the next couple of days.

Meanwhile in Mexico, residents and tourists in Puerto Vallarta are bracing for ferocious Hurricane Simon that is expected to be near or inland of the country's west-central coast.

The powerful Category 4 storm is expected to make landfall early Sunday

The US National Hurricane Center in Miami forecasts Simon will bring 25 to 50 centimetres of rain over Mexico's Southwest.

Some areas in the states of Michoacan, Colima and Jalisco could receive up to 76 centimetres, as the centre issues alerts for life-threatening flooding and mudslides especially in areas of steep terrain.