Media playback is unsupported on your device Media caption Gusts & floods: the impact of the storm

Weather forecasters warn of the risk of life-threatening flash flooding in parts of North and South Carolina, and Virginia, from storm Florence.

It has been downgraded from a hurricane to a tropical storm but continues to soak the East Coast area with rain, downing trees and damaging homes.

It is slowly grinding over the eastern states, with winds of 65mph (105km/h).

Five deaths have been linked to the storm and thousands of people have been staying in emergency shelters.

Evacuation warnings were issued for 1.7 million people in the region.

Image copyright Reuters Image caption Rescue workers from other parts of the country, including this crew from New York, have been helping in the Carolinas

All five deaths linked to the storm are in North Carolina:

A mother and her infant were killed in Wilmington when a tree fell on their home on Friday. Officials say the child's father was also transported to hospital for injuries

Two men in their 70s were killed in Lenoir County. One was killed when connecting an electrical generator, and family members say another man was killed in a wind-related death when checking on dogs outside his property

A woman died from cardiac arrest in the town of Hampstead after emergency responders had their route to her blocked by downed trees, a county official said

What is the latest on the storm?

The storm originally made landfall at Wrightsville Beach, North Carolina, on Friday morning as a category one hurricane.

Image copyright Getty Images Image caption Volunteers are helping to rescue residents from flooded homes

"Catastrophic fresh water flooding" is expected in parts of both the Carolinas, the National Hurricane Center said late on Friday local time.

Some parts of North Carolina have already seen surges as high as 10ft in places.

North Carolina Governor Roy Cooper said the hurricane was likely to "continue its violent grind for days" and described the severity of the downfalls as a "1,000 year event".

Media playback is unsupported on your device Media caption The Weather Channel uses virtual reality to show deadly storm surge

Florence is expected to dump 18 trillion gallons of rainwater on US soil, meteorologist Ryan Maue tweeted.

Almost 800,000 people are reported to be without power already in North Carolina, and officials have warned restoring electricity could take days or even weeks.

How are residents coping?

More than 20,000 residents have packed into North Carolina emergency shelters, and officials have told those still in the storm's path to stay in place.

In Jacksonville, North Carolina, officials had rescued more than 60 people overnight on Thursday from a hotel that was collapsing in the storm.

Parts of New Bern, North Carolina, which is home to 30,000 people, were 10ft underwater on Friday after local rivers flooded their banks.

Scores of residents in the riverfront city were plucked to safety, local reports say.

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The Cajun Navy, a volunteer rescue group, were among those travelling by boat around the town to help people who were trapped.

Officials have warned residents against entering attics, so as to avoid drowning, unless they have a means to cut through to the roof.

The White House said on Friday that President Donald Trump would travel to the region next week unless his trip would disrupt clean-up and rescue efforts.

Hurricanes A guide to the world's deadliest storms Hurricanes are violent storms that can bring devastation to coastal areas, threatening lives, homes and businesses. Hurricanes develop from thunderstorms, fuelled by warm, moist air as they cross sub-tropical waters.

Warm air rises into the storm. Air swirls in to fill the low pressure in the storm, sucking air in and upwards, reinforcing the low pressure. The storm rotates due to the spin of the earth and energy from the warm ocean increases wind speeds as it builds. When winds reach 119km/h (74mph), it is known as a hurricane - in the Atlantic and Eastern Pacific - or a typhoon in the Western Pacific. "Everybody has a plan until they get punched in the face. Well, we're about to get punched in the face."

Florida Mayor Bob Buckhorn, ahead of Hurricane Irma (2017) The central eye of calmer weather is surrounded by a wall of rainstorms.

This eyewall has the fastest winds below it and violent currents of air rising through it. A mound of water piles up below the eye which is unleashed as the storm reaches land.

These storm surges can cause more damage from flooding than the winds. "Urgent warning about the rapid rise of water on the SW FL coast with the passage of #Irma's eye. MOVE AWAY FROM THE WATER!"

Tweet from the National Hurricane Center The size of hurricanes is mainly measured by the Saffir-Simpson scale - other scales are used in Asia Pacific and Australia. Winds 119-153km/h

Some minor flooding, little structural damage.

Storm surge +1.2m-1.5m Winds 154-177km/h

Roofs and trees could be damaged.

Storm surge +1.8m-2.4m Winds 178-208km/h

Houses suffer damage, severe flooding

Storm surge +2.7m-3.7m Hurricane Sandy (2012) caused $71bn damage in the Caribbean and New York Winds 209-251km/h

Some roofs destroyed and major structural damage to houses.

Storm surge +4m-5.5m Hurricane Ike (2008) hit Caribbean islands and Louisiana and was blamed for at least 195 deaths Winds 252km/h+

Serious damage to buildings, severe flooding further inland.

Storm surge +5.5m Hurricane Irma (2017) caused devastation in Caribbean islands, leaving thousands homeless "For everyone thinking they can ride this storm out, I have news for you: that will be one of the biggest mistakes you can make in your life."

Mayor of New Orleans Ray Nagin ahead of Hurricane Gustav, 2008 Click arrow to proceed Loading ... Swipe to progress Go back to start

Is global warming to blame?

The relationship between climate change and hurricanes is a complex one.

Warmer seas power hurricanes. So as the temperature of ocean water goes up, we might expect the intensity of hurricanes to increase in future.

A hotter atmosphere can also hold more water, so this should allow hurricanes to dump more water on affected areas.

But there are so many factors that contribute to these rare events, it has been difficult to tease out clear trends from the data.