Hurricane Michael - one of the most powerful storms ever to strike the US mainland - has roared into the Florida coast bringing tree-snapping winds and towering waves.

The Category 4 storm made landfall at Mexico Beach at approximately 1:30pm local time, with wind speeds of 155mph - just shy of an extremely rare Category 5 storm.

The storm is the most powerful ever to hit north-west Florida. Earlier in the day, Florida Governor Rick Scott warned of "unimaginable devastation" calling it the worst storm to hit the area "in a century".

The first fatality caused by the hurricane was recorded near Greensboro, Florida, where Gadsden County sheriff's department said a “male subject” was killed by a tree toppling onto his house.

A child killed in Seminole County, Georgia, was the storm's second victim.

Causing major disruptions to oil and gas production in the Gulf even before its arrival, the storm was forecast to unleash waves as high as 14 feet (4.3 metres) above normal sea levels in some areas, the National Hurricane Center (NHC) said.

Mr Scott said that the thousands who had not evacuated - with more than 300,000 told to flee - should stay in their homes and that the worst thing they could do is "act foolishly". Thousands of National Guard members have been deployed or placed on alert to deal with the damage and anticipated rescues.

As it approached the area where southern Alabama, Georgia, and Florida meet wind speeds had dropped to 125mph, a Category 3 storm, before falling again to around 90mph. But officials warned it was dangerous to head out onto the road with trees and power lines down.

The storm was moved over the area and into Georgia on Wednesday night and is expected to hit parts of North and South Carolina on Thursday.

More than 400,000 people were said to be without power in Florida, Georgia and Alabama by Wednesday evening.

"We are catching some hell," Timothy Thomas, who rode out the storm with his wife in their second-floor apartment in Panama City Beach told Reuters. The area is close to where the storm made landfall.

Much of the area affected by the hurricane is rural and dotted with small tourist towns, beaches and wildlife reserves, as well as the state capital, Tallahassee, home to about 190,000 people

Footage from ISS shows Hurricane Michael from space

Florida Senator Marco Rubio also said “every storm's different, but this storm is a monstrosity."

Even Georgia is at risk, Federal Emergency Management Agency (Fema) Administrator Brock Long said during a news conference.

"The citizens in Georgia need to wake up and pay attention," he said after a meeting to brief Donald Trump on the disaster preparations.

"A hurricane of the worst kind," is how Mr Long described storm Michael.

Georgia Governor Nathan Deal said Michael is "unlike any storm that we have had in anybody's memory."

The state's peanut, pecan, and cotton crops could be devastated by the hurricane, potentially costing hundreds of millions in damage.

Mr Trump noted the storm started "innocently" and intensified into "a monster".

Hurricane Michael heads towards Florida

Michael grew from a tropical depression into a Category 4 hurricane in less than 72 hours.

The president said about the Florida panhandle: "Some of the areas are very poor," which makes it "very difficult for people without the necessary resources to leave."

He said he would likely travel to the affected region once the storm passes back out the ocean, which is expected to be later in the weekend.

The region was hit in recent weeks by Florence, which was originally a Category 4 storm but downgraded to a tropical storm.

Florence still caused flooding throughout the Carolinas and damage to several large farms, bridges, and roads.

Mr Long noted "any rain through North and South Carolina is not welcomed" as river beds have still not receded from the previous storm.

Mr Long also noted this morning is “the final call” for residents to get to a shelter or evacuate the area completely as roads in the panhandle are not safe to travel.

Those who try to last through "storm surge...don't typically live to tell about it," he said.

The surge is expected to produce waves and flooding in the range of nine to 18 feet (2.7 m to 5.5 m).

"Our priority is saving lives right now," Mr Long said, adding getting power lines back up and running and infrastructure clear and safe will be a priority.

"Power is going to be off for multiple weeks," he warned, adding Michael is "unprecedented”.

The wind speed puts Hurricane Michael just 7 mph short of being a Category 5 hurricane.

Hurricane Michael: record breaking storm hits the US Show all 16 1 /16 Hurricane Michael: record breaking storm hits the US Hurricane Michael: record breaking storm hits the US A damaged store in Panama City, Florida Getty Hurricane Michael: record breaking storm hits the US Waves crash into houses on the shore at Alligator Point in Franklin County, Florida Reuters Hurricane Michael: record breaking storm hits the US Haley Nelson of Panama City stands by her father's destroyed trailer home Getty Hurricane Michael: record breaking storm hits the US A damaged store in downtown Panama City, Florida Getty Hurricane Michael: record breaking storm hits the US A woman and her children wait in Panama City, Florida AFP/Getty Hurricane Michael: record breaking storm hits the US A stores windows are shattered by Hurricane Michael in Panama City, Florida Getty Hurricane Michael: record breaking storm hits the US A damaged apartment building in Panama City, Florida Getty Hurricane Michael: record breaking storm hits the US A damaged liquor store in Panama City Beach, Florida Reuters Hurricane Michael: record breaking storm hits the US A helicopter hovers over a damaged neighbourhood EPA Hurricane Michael: record breaking storm hits the US A man wades through a flooded street in Panama City, Florida EPA Hurricane Michael: record breaking storm hits the US A boathouse is damaged in the storm EPA Hurricane Michael: record breaking storm hits the US Charles Swaney of Panama City sits in the office of a damaged motel in Panama City, Florida AFP/Getty Hurricane Michael: record breaking storm hits the US A market is flooded in St. Marks, Florida Getty Hurricane Michael: record breaking storm hits the US A high-rise apartment building is damaged in Panama City Beach, Florida Reuters Hurricane Michael: record breaking storm hits the US Lenora Adams of Panacea, Florida evacuates a motel with her dog Reuters Hurricane Michael: record breaking storm hits the US Haley Nelson of Panama City stands by her father's destroyed trailer home Getty

There has never even been a Category 4 storm to hit the panhandle of Florida and the only Category 5 storm to hit the state was Hurricane Andrew in 1992.

Hurricane Camille hit Cuba, Alabama, Mississippi, and Louisiana in 1962 and a similar unnamed storm made landfall in 1935.

However, meteorologists and scientists have explained part of the problem is the government not acknowledging the role of climate change in the increased frequency of deadly and costly storms.

As environmental news outlet Grist reported: "six of the seven most damaging hurricanes in US history have hit in the past 10 years".

Hurricanes can be deadly, but they can also cause severe economic damage to the region in its path.

It is estimated Hurricane Irma, which primarily hit parts of southern Florida last year, cost the state $50bn in damage - the most expensive storm in state history.

Hurricane Andrew caused approximately $25 billion in damage. It was the most expensive storm in US history until Hurricane Katrina which caused an astonishing $108 billion across Louisiana, Texas, Alabama, and Mississippi in 2004. It also ravaged parts of tourist hub New Orleans.

Michael is expected to cause $30 billion in damage, according to a statement from forecaster Accuweather, adding: "The greatest impacts will be near and east of where the hurricane's eye makes landfall, and particularly along the coastline because of angry seas in a dangerous storm surge being driven inland by onshore winds."

The clean-up will come later, for now residents are just trying to survive the onslaught.

“My God, it's scary. I didn't expect all this,” said Bill Manning, 63, a grocery clerk who fled his camper van in Panama City for safer quarters in a hotel, only to see the electricity there go out.

“Panama City, I don't know if there will be much left,” he added.