Open this photo in gallery Sept. 16: One-year-old Oliver Kelly cries as he is carried off the sheriff's airboat during his rescue from rising flood waters in the aftermath of Hurricane Florence in Leland, N.C. JONATHAN DRAKE/Reuters

Latest updates

The deluge from tropical storm Florence continued to fall on the Carolinas Monday, after killing at least 23 people, flooding rivers and communities and leaving hundreds of thousands in the dark.

The Carolinas’ swollen rivers were beginning to swamp coal ash dumps and low-lying hog farms, raising concerns about water pollution.

Airlines cancelled more than 2,400 flights, and airports closed in Wilmington, N.C., Charleston, S.C. , and points farther inland. Airlines are bracing for more travel disruptions to come from tropical storm Isaac, which threatens vacation destinations in the Caribbean.

The Red Cross is raising funds for what is expected to be far-reaching damage. The onslaught could last for days, leaving a wide area under water from both heavy downpours and rising seas. “Surviving this storm will be a test of endurance, teamwork, common sense and patience," North Carolina Governor Roy Cooper said last Thursday.

Where is Florence now?

Florence made landfall as a Category 1 hurricane last Friday at 7:15 a.m. (ET) near North Carolina’s Wrightsville Beach. As it lumbered over the Carolinas, it lost speed but grew in area, becoming a tropical storm by late Friday and a tropical depression by Sunday.

On Monday, radar showed parts of the sprawling storm over six states, with North and South Carolina in the bull’s-eye.

As of 5 a.m., Florence’s winds had dropped to about 45 kilometres an hour, the U.S. National Weather Service said, with weakening forecast over the next 24 hours before intensifying again. The centre of the storm was about 200 km west southwest of Roanoke, Va., and moving northeast at 20 km/h, the weather service said.

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Open this photo in gallery In this NOAA satellite handout image captured at 7:45 a.m. ET, shows Hurricane Florence as it made landfall near Wrightsville Beach, North Carolina on September 14, 2018. Handout/Getty Images

The damage so far

After a weekend of high winds, torrential rain and rivers overflowing their banks, at least 23 people were dead by Monday. Here’s an overview of the other kinds of devastation Carolinians faced:

Heavy rains: Nearly 86 centimetres of rain fell from Thursday through Sunday in Swansboro, on the North Carolina coast, according to the National Weather Service.

Nearly 86 centimetres of rain fell from Thursday through Sunday in Swansboro, on the North Carolina coast, according to the National Weather Service. In the dark: About 575,000 outages were reported by early Monday, mostly in North Carolina.

About 575,000 outages were reported by early Monday, mostly in North Carolina. Destruction in New Bern: The mayor of one North Carolina community said 30 roads were rendered unpassable, 4,200 homes and more than 300 commercial buildings were damaged, 6,000 customers were without power and 1,200 residents were in shelters.

The mayor of one North Carolina community said 30 roads were rendered unpassable, 4,200 homes and more than 300 commercial buildings were damaged, 6,000 customers were without power and 1,200 residents were in shelters. Wilmington under siege: North Carolina’s eighth-largest city was cut off from the rest of the state by floodwaters from Florence. Officials plan to airlift food and water to the city of nearly 120,000 people.

The terrible trio: A hurricane’s destruction explained

Hurricanes are one of nature’s most powerful engines of destruction, turning warm sea water into wind and rain. Here’s a look at how those devastating forces played out in Florida. (For a more detailed primer on how hurricanes form, read more here.)

WIND

To be classified as a hurricane, a tropical storm has to have top wind speeds of 119 kilometres an hour or higher. Earlier this week, Florence had maximum sustained winds of 225 km/h, but slowed down to a Category 2 by Thursday, a 1 by Friday and a tropical storm by late Friday. Technically, a hurricane doesn’t have to make landfall to lash a coastal area with its strongest winds, the U.S. National Hurricane Center explains; “landfall” means that the centre of a hurricane has crossed onto a coastline, and the precise centre isn’t where the strongest winds are.

Past the 119-km/h threshold, the U.S. hurricane centre classifies storms in five categories of wind speed.

SAFFIR-SIMPSON SCALE Hurricane intensity is measured by a storm’s average wind speed WIND SPEED (km/h) STORM SURGE (m) Minimal damage Moderate damage 119–153 1.5–1.8 154–177 1.8–2.4 Extreme damage Extensive damage 178–208 2.7–3.7 209–251 4–5.5 Catastrophic damage 251+ 5.5+ the globe and mail, Source: reuters; NOAA SAFFIR-SIMPSON SCALE Hurricane intensity is measured by a storm’s average wind speed STORM SURGE (m) WIND SPEED (km/h) Minimal damage Moderate damage Extensive damage 119–153 1.5–1.8 154–177 1.8–2.4 178–208 2.7–3.7 Extreme damage Catastrophic damage 209–251 4–5.5 251+ 5.5+ the globe and mail, Source: reuters; NOAA SAFFIR-SIMPSON SCALE Hurricane intensity is measured by a storm’s average wind speed Minimal damage Moderate damage Extensive damage Extreme damage Catastrophic damage WIND SPEED (km/h) STORM SURGE (m) 119–153 1.5–1.8 154–177 1.8–2.4 178–208 2.7–3.7 209–251 4–5.5 251+ 5.5+ the globe and mail, Source: reuters; NOAA

STORM SURGE

A tropical cyclone is essentially a giant vaccuum of swirling water vapour, and the more powerful it is, the more water it sucks from some parts of the ocean to move to others. At one end, this creates astonishing drops in the water level, leaving boats and marine life stranded on exposed ocean floor, and at the other end, it creates storm surges, flooding streets and homes.

RAIN

Florance has dumped up to 100 centimetres of rain on North Carolina between Thursday and early Monday, and was continuing to dump water across the region, the national weather service said. Florence set a state record for rain from a hurricane, surpassing the previous high of 61 cm from Hurricane Floyd in 1999, Bryce Link, a meteorologist with private forecasting service DTN Marine Weather, told Reuters.

Another concern from an immense amount of rain is the toxicity in water supplies. North Carolina has roughly 2,100 industrial-scale pork farms containing more than nine million hogs. Florence’s heavy rain could cause an environmental disaster if waste from hog manure pits, coal ash dumps and other industrial sites washes into homes or threatens drinking water supplies.

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What makes Florence so rare?

Hurricane Florence was unusual in that it struck at the Carolinas from the east. Typically, storms that become hurricanes come to the U.S. east coast and the mid-Atlantic from the south, and curve outward to the sea. Most storms that hit the coastal U.S. tend to track further south near the Florida Keys, thanks to the jet stream that stretched across the northern United States. But since summer heat extends later, the jet stream has not moved the storm in the same way, and Florence is on a different track than most storms.

The last Category 4 hurricane to barrel straight toward the Carolinas was Hurricane Hazel in 1954, which was famous for its destructiveness. It was the deadliest and costliest hurricane of the 1950s, making landfall near Calabash, North Carolina before travelling along the Atlantic coast and affecting Virginia, Washington, D.C., West Virginia, Maryland, Delaware, New Jersey, Pennsylvania and New York. It was felt in Ontario as an extratropical storm and caused severe flooding.

Florence is the most dangerous of three tropical systems in the Atlantic. Tropical Storm Isaac was expected to pass south of Puerto Rico, Hispaniola and Cuba, while Hurricane Helene was expected to weaken over the eastern Atlantic.

How people on the coast prepared

Some 1.7 million people evacuated the area along the coast of North and South Carolina and Virginia. Service stations started running out of gas as far west as Raleigh, N.C., with bright yellow bags, signs or rags placed over the pumps to show they were out of order. Some store shelves were picked clean.

People began boarding up the sides of buildings and windows, while many stocked up on supplies. Steady streams of vehicles full of people, belongings and pets flowed inland Tuesday and will continue today, which has been declared the last day to safely evacuate. Governor Roy Cooper encouraged everyone on North Carolina’s coast to flee.

Floridians, usually accustomed to fleeing hurricanes by going north, began welcoming Carolinians coming south. Florida hotels offered special discounts for hurricane evacuees, and Florida ports opened their terminals to cruise ships making unexpected ports of call.

Open this photo in gallery Two people enter a restaurant with boarded windows in perpetration for the arrival of Hurricane Florence at Wrightsville beach, North Carolina, September 11, 2018. ANDREW CABALLERO-REYNOLDS

Open this photo in gallery A South Carolina state trooper directs traffic as D.O.T. workers move cones at an access ramp to I-26 Tuesday, Sept. 11, 2018, in Columbia, S.C. A lane reversal was implemented earlier in the day, utilizing all lanes for travel west between Charleston and Columbia in anticipation of the arrival of Hurricane Florence. Sean Rayford

What the federal government did

Days before Florence’s landfall, U.S. President Donald Trump vowed that federal agencies would be ready. “Don’t play games with it. It’s a big one,” he said in a videotaped message from the Rose Garden. Mr. Trump is expected to travel to areas hit by Hurricane Florence this week, once it has been determined that his travel would not disrupt any rescue or recovery efforts, the White House said last Friday.

For Puerto Ricans, Florence has brought back memories of the devastation from last year’s Hurricane Maria, and Mr. Trump’s widely criticized response to it. On a visit to the U.S. territory after Maria, Mr. Trump praised officials for a low loss of life, in a disaster the ultimately turned out to have 2,675 deaths, instead of the 64 initially estimated. Mr. Trump spent Thursday arguing on Twitter about Maria’s death toll, claiming without evidence that “3,000 people did not die.” He also called the count a move by Democrats to make him look bad. San Juan Mayor Carmen Yulin Cruz fired back at Mr. Trump, calling him “delusional.”

3000 people did not die in the two hurricanes that hit Puerto Rico. When I left the Island, AFTER the storm had hit, they had anywhere from 6 to 18 deaths. As time went by it did not go up by much. Then, a long time later, they started to report really large numbers, like 3000... — Donald J. Trump (@realDonaldTrump) September 13, 2018

Simply put: delusional, paranoid, and unhinged from any sense of reality. Trump is so vain he thinks this is about him. NO IT IS NOT. pic.twitter.com/K96H5O3NKM — Carmen Yulín Cruz (@CarmenYulinCruz) September 13, 2018

What you can do

The Red Cross has already set up a way to collect donations for relief from the impending storm, while fellow metropolis areas in Atlanta, Georgia and as far as Detroit are offering help and shelter.

Global Affairs Canada is advising Canadians not to travel to the storm-affected areas. Canadians who are already there can register with the department, which can provide consular assistance if needed.

Compiled by Globe staff

With reports from the Associated Press, New York Times News Service, The Canadian Press, Globe staff and Reuters