Florida is suffering the effects of Hurricanes Helene and Milton: Carolyn Gramling at Science News:
The rapid intensifications of both storms were fueled by the Gulf’s extremely warm water. Developing tropical storms can suck up heat from warm seawater, dragging the humid air upward where it condenses, releasing that heat into the storm’s core. As the storm moves forward, it pumps more and more water and heat into the air, and the spiraling winds will move faster and faster. Milton’s particularly explosive rate of growth may also be linked to its relatively compact size, compared with Helene (SN: 9/27/24).
Two separate reports published this week find that those warm Gulf waters were made hundreds of times more likely by human-caused climate change.
An analysis by the international World Weather Attribution, or WWA, initiative, released October 9, analyzed the role of climate change in contributing to Hurricane Helene’s intensification and its torrential rainfall, including as it moved inland across the Southern Appalachian Mountains.
Gulf of Mexico sea surface temperatures in the path of the storm were, on average, about 1.26 degrees Celsius (2.3 degrees Fahrenheit) warmer than they would have been in a world without climate change, the WWA researchers found. Or, to put it another way, the anomalously high temperatures along Helene’s path from development to landfall were made 200 to 500 times more likely due to climate change.
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Climate Central, based in Princeton, N.J., contributed to the WWA’s sea surface temperature analysis for Helene. And, in a separate alert released October 7, Climate Central reported that elevated sea surface temperatures in the southwestern Gulf of Mexico were also behind the “explosive” increase in intensity of Hurricane Milton. The analysis found that the sea surface temperatures in the Gulf were made 400 to 800 times more likely over the past two weeks due to human-caused climate change
The Tampa and St. Petersburg metro area is the most vulnerable to flooding damage in the U.S., according to a 2015 study by risk modeler Karen Clark & Co. Among the reasons the report cited: a shallow continental shelf off the coast and a funnel effect in Tampa Bay that together create the potential for a huge buildup of water that can inundate neighborhoods.
In addition, the metro area has experienced a building boom in recent decades that has sent the population soaring to about 3.2 million. Much of the development is on low-lying ground, with poorly developed drainage systems. A third of the area’s residents live within storm-surge zones.
“It’s the recipe for a huge storm-surge disaster,” said Jeff Masters, a former hurricane scientist at the National Oceanic and Atmospheric Administration and now a contributor at Yale Climate Connections, a news service.
In 2010, the Tampa Bay Regional Planning Council drew up the Tampa Bay Catastrophic Plan, in which a hypothetical Category 5 storm dubbed “Hurricane Phoenix” hit downtown Tampa with 160 mph winds and a 26-foot storm surge. The study projected that the city would have about 2,000 deaths and nearly $250 billion in damage.
In Tampa Bay, nearly 17,000 commercial properties and apartment buildings spanning 182 million square feet are in areas at high risk of flooding, according to real-estate data company CoStar Group. Billions of dollars of private and public funds have been invested in the redevelopment of downtown Tampa’s waterfront in recent decades. Many of these buildings are in vulnerable low-lying areas, according to data from CoStar.
Newer construction that was built to Florida’s current stringent building codes should stand up well to hurricane-force winds, storm specialists say. Other, more-established neighborhoods with older structures, however, are more susceptible.