Hurricane Helene has shortly intensified into an enormous Class 3 storm, with hurricane-force winds extending as much as 60 miles outward from the attention. Forecasters warn that Helene — which has wind speeds of close to 120 miles per hour — could possibly be lethal for these residing in coastal Florida, the place it’s anticipated to make landfall this night.
The Nationwide Hurricane Heart predicts storm surge as excessive as 20 toes in some components of Florida’s Massive Bend, a area between the panhandle and the peninsula. Storm surge, which describes an increase in sea stage, is probably the most harmful a part of tropical storms and has a lethal monitor file: In 2022, storm surge killed greater than 40 folks throughout Hurricane Ian. The storm can also be anticipated to inundate inland areas throughout a lot of the southeastern US with rain, dumping a foot or extra in components of southern Appalachia.
“This rainfall will seemingly end in catastrophic and probably life-threatening flash and concrete flooding,” the Nationwide Hurricane Heart mentioned early Thursday afternoon.
Helene may additionally disrupt a part of the epic monarch butterfly migration, which generally passes by way of the Massive Bend’s St. Marks Nationwide Wildlife Refuge in early October.
Helene is the eighth named storm in what has to date amounted to a considerably puzzling hurricane season. It began with a bang — June’s Hurricane Beryl grew to become the earliest Class 5 storm on file — after which a lot of August and September was unexpectedly quiet.
Many meteorologists, although, have been warning to not be fooled by this late-summer lull.
“Having multi-week intervals of quiet after which multi-week intervals of exercise may be very regular all through a hurricane season,” Brian McNoldy, a climatologist on the College of Miami, instructed me earlier this month. “I positively wouldn’t learn an excessive amount of into it.”
Plus, McNoldy mentioned, the ocean within the Gulf of Mexico has been — and nonetheless is — exceptionally sizzling, and sizzling water fuels hurricanes. Ocean warmth content material, a measure of how a lot warmth power the ocean shops, is at a file excessive for this time of yr.
Check out the chart under. The pink line is 2024 and the blue line is the common during the last decade.
This file ocean warmth is a transparent purpose why Hurricane Helene — which has been touring by way of the Gulf on its method to Florida — has intensified so shortly. Put merely, hotter water evaporates extra readily, and rising columns of heat, moist air from that evaporation are in the end what drive hurricanes and their fast intensification.
“The sea floor temperature and the ocean warmth content material are each file excessive within the Gulf,” McNoldy, who produced the chart above, instructed me. “That warmth on the floor and out there by way of a depth will give Helene all of the gas it must quickly intensify right now and into tomorrow.”
The file Gulf temperatures are only one sign of a extra widespread bout of warming throughout the North Atlantic that ramped up final yr.
It’s not solely clear what’s inflicting this warming, although scientists suspect a mixture of things together with local weather change — which raises the baseline ocean temperature — in addition to lingering results of El Niño, pure local weather variability, and even perhaps a volcanic eruption.
“That is out of bounds from the sorts of variability that we’ve seen in [at least] the final 75 years or so,” Ben Kirtman, director of the Cooperative Institute for Marine and Atmospheric Research, a joint initiative of the College of Miami and the Nationwide Oceanic and Atmospheric Administration (NOAA), instructed Vox in August. “That may be scary stuff.”
Replace, September 26, 3:30 pm ET: This story, initially revealed September 25, has been up to date with new data as Hurricane Helene approaches the Florida coast.
