Eerie detail in Hurricane Helene warning as 'unsurvivable' conditions loom in Florida

As Florida is pummelled by one of the most ferocious hurricanes in the region in years — which on Thursday officially made landfall, cutting power from hundreds of thousands of homes as the storm hit the US east coast — residents failing to evacuate have been given a bleak directive from exasperated authorities responding to weather radars.

Helene strengthened into a category four hurricane as it swept across Florida, with forecasters warning the enormous storm could create a "nightmare" surge in some areas, bring deadly winds and rain across much of southeastern US.

In a horrifying announcement, authorities in the state have described conditions as effectively "unsurvivable", due to the expected destruction from the storm, which spans approximately 645 kilometres and is producing destructive waves up to six metres high.

Police's grim directive to residents who fail to heed Florida hurricane evacuation orders

The Taylor County Sheriff’s Office, in the Big Bend, has taken the extraordinary step of asking those who fail to heed advice, and who have voluntarily chosen to remain in their homes, to identify themselves with permanent marker on their limbs. This, the department said, will make identifying bodies quicker.

"We are requesting that all residents, guests, and evacuees refrain from returning to the area until officially directed by the Emergency Operations Center," the sheriff's office said on social media.

"Returning prematurely poses significant risks due to expected heavy flooding and other hazards. Many roads will be impassable, there may be downed power lines, fallen trees, and other dangerous conditions.

Live coverage: Hurricane Helene makes landfall in Florida as catastrophic Category 4 storm

"If you or someone you know chose not to evacuate, PLEASE write your, name, birthday and important information on your arm or leg in A PERMANENT MARKER so that you can be identified and family notified." Videos on social media showed some people in Florida voluntarily remaining in their homes.

Hundreds of thousands without power already

Category four hurricanes sustain winds over 210 km/h that can severely damage homes, snap trees and down power lines. Strong winds have already cut power to over 250,000 homes and businesses in Florida.

Life-threatening storm surges of up to six metres were expected in the Big Bend area of Florida. Hurricane warnings and flash flood warnings extended far beyond the coast up into northern Georgia and western North Carolina. The governors of Florida, Georgia, the Carolinas and Virginia have all declared emergencies in their states.

Beyond Florida, up to 25 centimetres of rain has fallen in the North Carolina mountains, with up to 36 centimetres more possible before the deluge ends, setting the stage for flooding that forecasters warned could be worse than anything seen in the past century.

Many were heeding the mandatory evacuation orders that stretched from the Panhandle south along the Gulf Coast in low-lying areas around Tallahassee, Gainesville, Cedar Key, Lake City, Tampa and Sarasota. One Tampa resident, Ashly Cox, posted to social media to say her and her boyfriend were ignoring the mandatory evacuation warning to stay home, to the dismay of her followers.

Along Florida's Gulf Coast, school districts and multiple universities cancelled classes. Airports in Tampa, Tallahassee and Clearwater were closed on Thursday, while cancellations were widespread elsewhere in the state and beyond.

Helene is forecast to be one of the largest storms in breadth in years to hit the region, said Colorado State University hurricane researcher Phil Klotzbach. He said since 1988, only three Gulf hurricanes were bigger than Helene's predicted size: 2017's Irma, 2005's Wilma and 1995's Opal.

Helene is the eighth named storm of the Atlantic hurricane season, which began on June 1.

The National Oceanic and Atmospheric Administration has predicted an above-average Atlantic hurricane season this year because of record-warm ocean temperatures.

with AAP

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