Storm Idalia hits Florida – as scientists spell out the links between hurricanes and the climate crisis

Scientists are sounding the alarm on human-caused climate change’s impact on hurricanes such as Idalia, which rapidly intensified over a warm Gulf of Mexico before making landfall in Florida on 30 August.

Florida has now begun to assess the damage from Idalia’s flooding after the powerful storm inundated coastal communities. The system knocked out power to thousands as it advanced up the southeastern US coast.

After crossing the state, Idalia hit neighboring Georgia and weakened to a tropical storm. Nevertheless, it still drenched the region with up to 10 inches of rain. State officials said first responders including search and rescue teams were operational. However, they warned it could take time to reach more remote areas blocked by fallen trees or high water.

Idalia: Category 3 Hurricane

Idalia struck as an “extremely dangerous” Category 3 hurricane in Florida’s marshy Big Bend area. It landed at around 7:45 am (11:45 GMT) on 30 August, according to the US National Hurricane Center (NHC). Its winds measured approximately 125 miles an hour.

In the Tampa Bay area, streets were submerged and flood waters swept across yards. Just north in the city of Tarpon Springs, residents waded to safety as homes and apartments were inundated.

With the White House calling for storm vigilance, the Federal Emergency Management Agency (FEMA) deployed more than 1,000 emergency personnel to the disaster zone. FEMA Administrator Deanne Criswell stated that:

Idalia is the strongest storm… to make landfall in this part of Florida in over 100 years.

The storm travelled over the Gulf of Mexico, which scientists say is experiencing a “marine heat wave”. This energised Idalia’s winds as it raced towards Florida. Record-breaking temperatures off Florida are expected to amplify Atlantic storms this season, with scientists blaming human-caused climate change for the overall warming trend.

Criswell told a press conference on Wednesday that:

These storms are intensifying so fast that our local emergency management officials have less time to warn and evacuate and get people to safety.

Forecasts in chaos

Back in May, the US National Oceanic and Atmospheric Administration (NOAA) predicted a “near normal” Atlantic hurricane season. This nominally runs from June 1 to November 30. That was in large part because of the El Nino global weather pattern. El Nino causes a higher-than average ‘vertical wind shear’ in the Atlantic, which in turn suppresses hurricane activity.

Allison Wing, an atmospheric scientist at Florida State University, stated that:

If you have big changes in the wind with height, that tends to import dry, lower-energy air into the core of a tropical cyclone and prevent it from strengthening.

However, in August, NOAA increased its forecast prediction for the season to ‘above normal’. This was based on ocean and atmospheric conditions like record-warm Atlantic sea-surface temperatures that:

are likely to counterbalance the usually limiting atmospheric conditions associated with the ongoing El Nino event.

Wing added that:

It’s been a sort of tricky year in terms of thinking about the whole seasonal forecast because we have these two opposing factors.

The effects of climate change

In one eye-catching example, on July 24 a buoy off the southern tip of Florida recorded a peak temperature of 38.4 Celsius. This kind of reading is more commonly associated with hot tubs, and a possible new world record.

Michael Mann, a climatologist at University of Pennsylvania, said:

Warm waters, both at the surface of the ocean and beneath, provide the fuel that intensifies tropical storms and hurricanes… That allows them to both intensify faster and attain higher maximum intensities.

Apart from affecting the maximum intensity of hurricanes, climate change can also increase the amount of rain they shed. For instance, last year climate change boosted Hurricane Ian’s rainfall by at least 10%, according to recent research. You still need the right conditions to lead to hurricane formation. However, when they come along, storms will interact with warming oceans to generate fiercer winds and cause bigger storm surges.

Wing explained that:

You can think of climate change as sort of like loading the dice. There’s still a variety of different possible outcomes for any individual storm, but you have a greater chance of having those high-intensity storms.

Additional reporting via Agence France-Press

Featured image via Flikr/NASA Goddard Space Flight Center