MIAMI (NYTIMES) - Tropical Depression Fred moved through the US south-east on Tuesday (Aug 17), bringing with it heavy rains and touching off several tornadoes, one day after it made landfall in the Florida Panhandle.
As at 5pm on Tuesday, Fred was about 145km west-south-west of Asheville, North Carolina, with maximum sustained winds of 40kmh, the National Weather Service said. It was moving north-north-east at 37kmh.
Throughout the night, the Weather Service issued at least 10 tornado warnings in North and South Carolina, meaning that a tornado had been spotted or picked up on a radar.
Parts of those two states and Virginia were under a tornado watch up till 2am on Wednesday.
A few tornadoes were likely, along with hail, and wind gusts of up to 96kmh, the Weather Service said.
Several tornadoes were reported across the region on Tuesday, including in Edgefield, South Carolina, and in Iredell County, North Carolina, about 80km north of Charlotte. There were no immediate reports of injuries.
In Greenville County, South Carolina, public school students and teachers were instructed to shelter in place on Tuesday afternoon after a tornado warning was issued for the area, local media outlets reported. The warning was later cancelled.
The severe weather knocked out power in some areas and caused flight delays across the South, where tornado warnings remained in effect in several states on Tuesday evening.
Heavy rain was expected to continue across some parts of the Appalachian Mountains until Thursday, according to the Weather Service, which said there was a risk of landslides in North Carolina and of flash flooding across the south-east and mid-Atlantic.
Fred came ashore on Monday near Cape San Blas, Florida, as a tropical storm.
President Joe Biden later approved an emergency declaration for 23 Florida counties, and the storm brought flooding to some areas.
But the storm was downgraded to a tropical depression early on Tuesday morning, and the National Hurricane Centre said that elevated water levels along the coastline were expected to subside after high tide.
Videos circulating on social media on Monday evening showed heavy flooding in Southport, Florida, about 16km north of Panama City. But there did not appear to be significant damage in Florida as at Tuesday morning.
Forecasters are also monitoring Tropical Storm Grace, the seventh named storm of the Atlantic season, which formed in the eastern Caribbean on last Saturday morning and is expected to become a hurricane as it approaches Mexico.
Grace, which made landfall in Haiti on Monday as a tropical depression, restrengthened into a tropical storm early on Tuesday morning, the National Hurricane Centre said.
The storm's heavy rains brought the potential for mudslides and flooding that could hamper recovery efforts from a 7.2-magnitude earthquake that struck the country three days earlier.
Fred formed a week ago as the sixth named storm of the 2021 Atlantic hurricane season. It became a tropical storm just south of Puerto Rico last Tuesday.
The next day, the authorities there said that power outages and flooding had been reported across the island.
The storm made landfall in the Dominican Republic on Wednesday, where heavy rain caused floods in some parts of Santo Domingo and uprooted trees.
Fred then brought heavy rain to eastern Cuba and some of the Bahamas on Friday morning before passing near the Florida Keys on Saturday.
The links between hurricanes and climate change are becoming more apparent.
A warming planet can expect to experience stronger hurricanes over time, and a higher incidence of the most powerful storms - though the overall number of storms could drop because factors like stronger wind shear could keep weaker storms from forming.
Hurricanes are also becoming wetter because of more water vapour in the warmer atmosphere; scientists have suggested that storms like Hurricane Harvey in 2017 produced far more rain than they would have without the human effects on climate.
Also, rising sea levels are contributing to higher storm surges - the most destructive elements of tropical cyclones.
A major United Nations climate report released last week warned that nations had delayed curbing their fossil fuel emissions for so long that they could no longer stop global warming from intensifying over the next 30 years, leading to more frequent life-threatening heat waves and severe droughts.
Tropical cyclones have most likely become more intense over the past 40 years, the report said, a shift that cannot be explained by natural variability alone.
Ana became the first named storm of the season on May 23, making this the seventh year in a row that a named storm developed in the Atlantic before the official start of the season on June 1.
The most recent named storm in the Atlantic was Hurricane Elsa in early July. Elsa cut through Cuba and then Florida, eventually making its way into New York City, where heavy rainfall from the storm flooded subway stations and roadways.
In May, scientists with the National Oceanic and Atmospheric Administration (NOAA) forecast that there would be 13 to 20 named storms this year, six to 10 of which would be hurricanes, and three to five major hurricanes of Category 3 or higher in the Atlantic.
Last week, in a mid-season update to the forecast, they continued to warn that this year's hurricane season would be an above average one, suggesting a busy end to the season.
Mr Matthew Rosencrans of NOAA said that an updated forecast suggested that there would be 15 to 21 named storms, including seven to 10 hurricanes, by the end of the season on Nov 30.
Last year, there were 30 named storms, including six major hurricanes, forcing meteorologists to exhaust the alphabet for the second time and move to using Greek letters.
It was the highest number of storms on record, surpassing the 28 from 2005, and included the second-highest number of hurricanes on record.