Five dead from Hurricane Helene, but storm downgraded to Cat 1

At least five people have died in the south-eastern United States following Hurricane Helene's landfall on Thursday evening, but by Friday morning the storm had been downgraded to a Category 1 storm, authorities said.

The National Weather Service said the hurricane made landfall on the west coast of Florida as a Category 4 hurricane - the second highest category - but had lost steam. The casualties were in Florida and Georgia.

Florida Governor Ron DeSantis said one person had died when a traffic sign had fallen and hit a car. CNN reported that two people died in Georgia when they were caught in a tornado, which was said to have been triggered by the hurricane.

"Helene" made landfall with wind speeds of up to 225 kilometres per hour in the Big Bend region of northern Florida late in the evening as an "extremely dangerous hurricane."

The US Federal Emergency Management Agency (FEMA) had urgently warned several states about the storm.

The entire west coast of Florida and the Big Bend region in the state's north were particularly affected. According to data from the Poweroutage.us website, around 975,000 households in Florida were without electricity by Thursday evening.

Tropical cyclones form over warm ocean waters. Experts say global warming increases the probability of severe storms. The hurricane season begins in the Pacific on May 15 and in the Atlantic on June 1. The season ends in both regions on November 30.