Hurricane Helene has been rampaging via the southeastern United States immediately, inflicting catastrophic flooding and killing at the very least 40 folks in 4 states. The demise toll is prone to rise.
The storm slammed ashore as a Class 4 hurricane on Thursday night with most sustained winds of 140 mph. It additionally pushed up inundating storm surges. As I am scripting this on Friday afternoon, it has been downgraded to a tropical storm — nevertheless it nonetheless poses lethal risks.
“Historic, catastrophic and life- threatening flash and concrete flooding, together with quite a few vital landslides, will proceed throughout parts of the Southern Appalachians via this night,” in accordance with the Nationwide Hurricane Heart.
Together with Helene, america has now skilled a report eight Class 4 or Class 5 Atlantic hurricane landfalls previously eight years (2017-2024). “That’s as many Cat 4 and 5 landfalls as occurred within the prior 57 years,” writes meteorologist Jeff Masters.
Hurricanes feast on oceanic warmth and switch it into the power of their winds. “A warmer ocean will permit hurricanes to develop extra highly effective, assuming that the opposite components that energy hurricanes, together with low wind shear and a moist ambiance, are current,” in accordance with Masters.
Because it seems, this time there was record-setting warmth for Helene to devour, which after all is linked to local weather change. However earlier than I delve into extra element on potential local weather connections, take a look at this round-up of distant sensing imagery of the storm, highlighting a few of its vital options:
GOES-16 Satellite tv for pc Imagery
Hurricane Helene’s astonishing evolution over the course of simply two and a half days is seen on this animation of GOES-16 satellite tv for pc photographs — from a tropical disturbance within the Caribbean Sea to a devastating Class 4 hurricane alongside Florida’s Gulf of Mexico shoreline. (Credit score: CSU/CIRA & NOAA).
As seen by the GOES-16 satellite tv for pc, Helene evolves right into a Class 4 storm with a watch wall crackling with lightning. (Credit score: CSU/CIRA & NOAA).
Hurricane Helene makes landfall on Sept. 26, 2024 as a Class 4 storm with most sustained winds of 140 mph in Florida’s Massive Bend area, as seen on this infrared view acquired by the GOES-16 satellite tv for pc. (Credit score: CSU/CIRA & NOAA).
A 12-hour time lapse of GOES-16 satellite tv for pc imagery reveals Hurricane Helene making landfall, and charging inland, the place it has triggered catastrophic rainfall and lethal inundation. (Credit score: CSU/CIRA & NOAA).
Again to Local weather Connections…
Even earlier than something had actually occurred, hurricane specialists had been fearful. Because the College of Miami’s Brian McNoldy put it on Sept. 17, “There’s nothing to have a look at but, however a broad low stress system might take form on Friday-Saturday east of Honduras then consolidate and monitor north from there.”
McNoldy and others had been involved due to the record-setting hurricane gasoline within the western Caribbean — sky-high oceanic heat. “All of which means ought to something type within the western Caribbean quickly, the ocean will present limitless high-octane gasoline for it.”
Ocean warmth content material — that means the thermal power saved in a quantity of the ocean — has been working at record-high values within the Caribbean Sea. (Credit score: Brian McNoldy, College of Miami)
As we now know, one thing did certainly type — a disturbance that exploded into Hurricane Helene at a wide ranging tempo.
However on Sept. 23, Helene had not but became a bona fide storm. Even so, McNoldy was rising more and more involved, and he predicted the disturbance would very doubtless intensify quickly as soon as it entered the Gulf of Mexico.
“Not solely is the ocean floor temperature alongside its path a toasty 30-31C, the nice and cozy water runs deep, producing extraordinarily excessive ocean warmth content material… an limitless supply of gasoline,” he wrote. “A heat ocean is not all the things on the subject of hurricanes, nevertheless it’s rather a lot.”
Because the storm moved from the Caribbean into the Gulf of Mexico, it appears to have ate up a big, tongue-shaped patch of very hot water, which you’ll see right here:
A tongue-shaped patch of unusually heat water is seen right here extending into the Gulf of Mexico on Sept. 23, 2024. The visualization was created utilizing information from satellites and devices on the floor. (Credit score: NASA Worldview.)
The nice and cozy tongue prolonged north from the Caribbean Sea into the Gulf of Mexico towards the Florida Panhandle. It was an indication that the Loop Present, which helps funnel water from the Caribbean into the Gulf of Mexico, had shed a heat eddy “that was lingering uncomfortably near U.S. shores,” in accordance with NASA.
As McNoldy predicted, Helene intensified very quickly, sped rapidly landward, after which charged deeply inland.
And as we have seen, it has dumped huge quantities of water, resulting in calamitous flooding. Right here, too, there’s a potential local weather connection. That is as a result of warming spurs elevated evaporation of water into the air, which in flip can maintain extra water vapor when it is hotter. The end result: juiced up rainfall. Furthermore, because the water vapor condenses into liquid, it releases warmth, which may also help maintain your complete chain of occasions.
We do not know but simply how a lot local weather change affected Helene. So within the weeks forward, scientists will doubtless produce “attribution” research that may doubtlessly shed extra mild on the connections between Helene and local weather change. Keep tuned for these.
Within the meantime, for extra element on this topic, I extremely advocate Jeff Masters’ in-depth look: “4 methods local weather change doubtless made Hurricane Helene worse“
