This article is more than 1 year old

This article is more than 1 year old

Hurricane Michael has whipped up into a category 4 monster storm as it makes its final approach to the Florida Panhandle on Wednesday, on track for a catastrophic, record-breaking landfall mid-Wednesday as the region’s strongest storm in living memory, with gusts up to a deadly 165mph.

A category 4 storm has never made landfall in the panhandle before, and Michael’s vast size means the effects will be felt along the coast from New Orleans to Tampa Bay, and inland as far as the Carolinas. It is forecast to blow in with sustained winds of 145mph and still to be a hurricane by the time it reaches southern Georgia, with winds continuing over 75mph. A tornado watch is in effect for the region.

More than 500,000 people were either ordered or advised to evacuate as Michael, fueled by the warm waters of the Gulf of Mexico, closed in, packing sustained winds of 145mph and a life-threatening storm surge of up to 14ft.

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Authorities warned that anybody who chose not to evacuate would be on their own, with conditions already too hazardous for emergency workers to operate.

“Nobody’s coming out to save your life today,” Florida governor Rick Scott said on CNN.

“We’ve done everything we can to tell people to evacuate and some people have unfortunately chosen not to. I’m scared to death if there’s any kids who didn’t make that choice on their own.”

A category 4 storm has never made landfall in Florida’s Panhandle before, and Michael’s vast size meant the effects would be felt along the coast from New Orleans to Tampa Bay, and inland as far as the Carolinas. More than 20 million people in five states remained under either a hurricane or tropical storm warning, while areas in North and South Carolina flooded by Hurricane Florence last month braced for more rainfall.

The fast-moving tropical cyclone’s outer bands were already causing torrential rain in Panama City Beach and Apalachicola by 8am on Wednesday with the eye of the storm 90 miles away and travelling north at 13mph. It was expected to make landfall by early afternoon and move swiftly off to the north-east, with winds of 75mph stretching as far as the state capital, Tallahassee.

“This is a truly historic and very dangerous storm,” Ken Graham, the director of the National Hurricane Center (NHC) in Miami, said in a Wednesday morning briefing. “Even 185 miles away from the centre, tropical storm force winds are still occurring. It’s still a hurricane in Georgia, stretching over the Carolinas by the time it’s all done.”

The famous white sand beaches of the panhandle will be engulfed.

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A life-threatening storm surge of between nine and 13ft (4 metres) is expected along the coast.

“THIS IS YOUR LAST CHANCE to evacuate before conditions start deteriorating within the next few hours,” Governor Scott tweeted early on Wednesday.

More than 20 million people across five states, Florida, Alabama, Georgia and the Carolinas, were under a hurricane or tropical storm warning by Tuesday evening. Evacuations spanned 22 counties from the Florida Panhandle into north central Florida. But fears lingered that some failed to heed the calls to get out of Michael’s way as the hard-charging storm began speeding north over the warm waters of the Gulf of Mexico.

Jack Sillin | weather.us (@JackSillin) #Michael making a big show of clearing/warming its eye in the past 15 minutes or so. As horrifying as it is to see this happen so close to land, it's also incredible to be able to watch in near-real time -> https://t.co/uYMgn3138I pic.twitter.com/B1Qzd64zRl

The storm has claimed at least 13 lives during its northerly march through the western Caribbean and Central America.

Donald Trump made a disaster declaration for Florida that allows the resources of the federal emergency management agency (Fema) to be deployed. Early reports of flooding from the Panhandle were received before nightfall.

Authorities upgraded the hurricane to a category 4 status in the early hours of Wednesday morning. They said category 4 storms were “extremely dangerous” and had the potential to devastate large areas and leave homes without power for weeks.

Some officials were worried that they were not seeing a rush of evacuees. “I am not seeing the level of traffic on the roadways that I would expect when we’ve called for the evacuation of 75% of this county,” the Bay county sheriff, Tommy Ford said.

Officials including Trump, Scott and Andrew Gillum, the Tallahassee mayor aiming to become governor in next month’s election, all urged citizens not to underestimate the storm.

Facebook Twitter Pinterest A satellite image of Hurricane Michael, which is expected to make landfall on Wednesday, approaching the US coast. Photograph: Noaa/Handout/EPA

Speaking at an emergency management briefing on Tuesday morning, Scott, who declared a state of emergency in 35 of Florida’s 67 counties from the Panhandle to Tampa Bay, said the forecast “keeps getting more dangerous. This storm will be life-threatening and extremely dangerous.”

At the White House, Trump told reporters the federal government was “very well-prepared”.

In western Cuba, Michael triggered flash floods and mudslides in mountain areas. Disaster agencies in El Salvador, Honduras and Nicaragua reported 13 deaths as roofs collapsed and residents were carried away by swollen rivers. Six people died in Honduras, four in Nicaragua and three in El Salvador. Authorities were searching for a boy swept away by a river in Guatemala. Heavy rains swamped the region at the weekend after Michael formed off the coast of Honduras.

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Scott activated hundreds of national guard members and waived tolls to encourage evacuations. He also warned caregivers at north Florida hospitals and nursing homes to do all possible to assure the safety of the elderly and infirm. Following Hurricane Irma last year, 14 people died when a south Florida nursing home lost power and air conditioning.

“If you’re responsible for a patient, you’re responsible for the patient. Take care of them,” Scott said.

Sheriff David Morgan of Escambia county bluntly advised residents choosing to ride it out: “If you decide to stay in your home and a tree falls on your house or the storm surge catches you and you’re now calling for help, there’s no one that can respond to help you,” Morgan said.

Facebook Twitter Pinterest A woman spray paints the words ‘Calm down Michael’ on the plywood over her daughter’s business in preparation for the arrival of Hurricane Michael in Mexico Beach, Florida. Photograph: Joe Raedle/Getty Images

Associated Press contributed to this report