Hurricane Helene has rapidly intensified into a massive Category 3 storm, with gale-force winds extending up to 60 miles out of the eye. Forecasters warn that Helene, which has winds of nearly 120 miles per hour, could be deadly for those living on the Florida coast, where it is expected to make landfall tonight.
National Hurricane Center predicts storm surge as tall as 20 feet in some parts of Florida’s Big Bend, a region between the Panhandle and the Peninsula. Storm surge, which describes a rise in sea level, is the most dangerous part of tropical storms and has a deadly track record: In 2022, storm surge killed more than 40 people during Hurricane Ian. The storm is also expected to inundate inland regions of much of the southeastern United States with rain, dumping a foot or more in parts of the southern Appalachians.
“This rainfall will likely cause catastrophic and life-threatening urban flash flooding,” the National Hurricane Center said. saying early Thursday afternoon.
Helene could also alter some of the Epic Monarch Butterfly Migrationwhich typically passes through Big Bend’s St. Marks National Wildlife Refuge in early October.
Helene is the eighth named storm in what has so far been a something disconcerting hurricane season. It all started strong: the month of June Hurricane Beryl It became the first Category 5 storm on record, and then much of August and September was unexpectedly quiet.
However, many meteorologists have warned not to be fooled by this late summer lull.
“Having calm periods of several weeks and then periods of activity of several weeks is very normal during a hurricane season,” Brian McNoldya climatologist at the University of Miami told me earlier this month. “I definitely wouldn’t put too much stock in it.”
Additionally, McNoldy said, the ocean in the Gulf of Mexico has been (and continues to be) exceptionally warm, and warm water fuels hurricanes. Ocean heat content, a measure of how much thermal energy the ocean stores, is at a record level for this time of year.
Take a look at the chart below. The red line is 2024 and the blue line is the average for the last decade.
This record ocean heat is a clear reason why Hurricane Helene, which has been passing through the Gulf on its way to Florida, has intensified so quickly. Simply put, warmer water evaporates more easily, and the rising plumes of warm, moist air from that evaporation are ultimately what drives hurricanes and their rapid intensification.
“He sea surface temperature and ocean heat content are record highs in the Gulf,” McNoldy, who produced the graph above, told me. “That heat at the surface and available at depth will give Helene all the fuel she needs to rapidly intensify today and tomorrow.”
Record-breaking Gulf temperatures are just one sign of a bigger situation generalized warming attack across the North Atlantic increased last year.
It is not entirely clear what is causing this warming, although scientists suspect a combination of factors including climate change, which raises the ocean’s base temperature, as well as the lingering effects of the The Childnatural climate variability and perhaps even a volcanic eruption.
“This is outside the bounds of the types of variability we’ve seen in (at least) the last 75 years or so,” Ben Kirtmanthe director of the Cooperative Institute for Marine and Atmospheric Studies, a joint initiative of the University of Miami and the National Oceanic and Atmospheric Administration (NOAA), told Vox in August. “That can be a scary thing.”
Update, September 26 at 3:30 pm ET: This story, originally published on September 25, has been updated with new information as Hurricane Helene approaches the Florida coast.
