Hurricane Sally, a plodding storm with winds of 85mph, crept toward the northern US Gulf coast early Tuesday as forecasters warned of potentially deadly storm surges and flash floods with up to 2ft of rain and the possibility of tornadoes.
Hurricane warnings stretched from Grand Isle, Louisiana, to Navarre, Florida, but forecasters, while stressing “significant” uncertainty, kept nudging the predicted track eastward, easing fears in New Orleans, which was once in Sally’s crosshairs.
The storm was forecast to reach land near the Alabama-Mississippi state line by late Tuesday or early Wednesday.
Stacy Stewart, a senior specialist with the National Hurricane Center (NHC), said people should continue to take the storm seriously since “devastating” rainfall is expected in large areas. People could drown in the flooding, he said.
“This is going to be historic flooding along with the historic rainfall,” Stewart said. “If people live near rivers, small streams and creeks, they need to evacuate and go somewhere else.”
The storm was moving at only 2mph before dawn on Tuesday, centered about 115 miles south-south-east of Biloxi, Mississippi, and 60 miles east-south-east of the mouth of the Mississippi river.
Forecasters expected Sally to turn north on Tuesday afternoon, moving near the coast of south-eastern Louisiana later in the day, and then travel slowly north-north-eastward through Wednesday, with top winds increasing to 110mph nearly category 3, before blowing ashore.
Florida’s governor, Ron DeSantis, declared an emergency in the Panhandle’s western-most counties, which were being pummeled by rain from Sally’s outer bands early on Tuesday. The threat of heavy rain and storm surge was exacerbated by the storm’s slow movement.
Donald Trump issued emergency declarations for parts of Louisiana, Mississippi and Alabama, and tweeted that residents should listen to state and local leaders.
Alabama’s governor, Kay Ivey, sought the presidential declaration after the National Weather Service (NWS) in Mobile, Alabama, warned of the increasing likelihood of “dangerous and potentially historic flooding”, with waters rising as much as 9ft above ground in parts of the Mobile metro area.
While the threat to Louisiana appeared to be easing, authorities remained on guard, closing gates along networks of waterways that could be pushed over their banks by the possible surge from the Gulf.
The south-western part of the state was pummeled by Hurricane Laura on 27 August and an estimated 2,000 evacuees from that storm were sheltered in New Orleans, mostly in hotels.
Monday marked only the second time on record, forecasters said, that five tropical cyclones swirled simultaneously in the Atlantic basin. The last time that happened was in 1971. None of the others were expected to threaten the US this week, if at all, and one was downgraded to a low pressure trough on Monday evening.
The extraordinarily busy hurricane season – like the catastrophic wildfire season on the west coast – has focused attention on the role of climate change. Scientists say global warming is making the strongest of hurricanes, those with wind speeds of 110mph or more, even stronger. Also, warmer air holds more moisture, making storms rainier, and rising seas from global warming make storm surges higher and more damaging.
In addition, scientists have been seeing tropical storms and hurricanes slow down once they hit the US by about 17% since 1900, and that gives them the opportunity to unload more rain over one place, as 2017’s Hurricane Harvey did in Houston.