Hurricane Idalia: Warm Florida waters fuelling a fiery storm

Are hurricanes getting worse with time?

Power-hungry hurricanes are formed when thunderstorms pull in warm surface air. Ocean surface waters must be at least 80 degrees for that to happen. The system intensifies as it absorbs all that warm water. Surface temperatures at some places in Florida are higher than 90 degrees Fahrenheit (32 degrees Celcius). According to hurricane researcher Brian McNoldy, the Florida Gulf Coast water “is absurdly warm,” he told the Associated Press. 

The fact that we had a blue supermoon event also makes things intense, as its gravitational pull can make for high tides. There have also been reports of extreme water temperatures in Florida in July, which is bad for corals. This also brings us to the fact that Florida’s western coast doesn’t have deep waters. Cold waters cut through the storm and stall the formation of hurricanes. A sizable depth ensures that waters don’t turn extremely hot, which Florida’s western coast doesn’t have.

It seems like all odds were stacked against the rapid formation of Hurricane Idalia. According to a new study published in Nature Communications, the researchers have studied the rapid intensification (RI) of tropical cyclones observed worldwide. RI occurs when a tropical storm intensifies dramatically over a short period, thus making the prediction of correct forecasting particularly challenging.

Of late, the IR has increased in the coastal areas of the US, which the researchers say warrants additional attention. Additionally, global surface temperatures have increased at a rate of 0.18 °C per decade since 1981, which is more than twice that since 1880, noted the study. 

The researchers of the study analyzed trends of RI events across global oceans during 1980–2020 and found that RI events increased significantly more rapidly in offshore regions than in open oceans.

Does climate change have a role to play?

The researchers of the study noted that the effects of global increases in sea surface temperatures and Pacific Decadal Oscillation (PDO) - a climatic event that covers vast areas of the Pacific Ocean over periods of 20 to 30 years - has a role to play in the increase in rapid intensification of tropical cyclones.

The researchers said when it comes to a single storm such as Idalia, it’s hard to blame its rapid intensification on climate change, according to AP. However, other research has shown that warming oceans leads to RI, thus increasing the strength of hurricanes.

Interesting Engineering reported a study in April about how the east and Gulf coasts of the US are likely to experience frequent and stronger hurricanes due to changes in air patterns as the planet warms. The study identified Florida as the region most in danger.

Idalia is expected to move offshore today, but it is likely to remain a tropical storm as it does so, said the National Hurricane Center. But a Storm Surge Watch for some parts of North Carolina is in place, meaning life-threatening inundation is possible.

Georgia and the Carolinas - the US states of South Carolina and North Carolina - also received heavy rains.

President Biden tweeted: “This morning, I spoke with Governor DeSantis to inform him that we've approved the Emergency Declaration for Florida as they prepare for Hurricane Idalia, and FEMA has pre-deployed personnel and assets. Florida has my full support as they prepare for Idalia and its aftermath.”

Study abstract:

Rapid intensification (RI) is an essential process in the development of strong tropical cyclones and a major challenge in prediction. RI in offshore regions is more threatening to coastal populations and economies. Although much effort has been devoted to studying basin-wide temporal-spatial fluctuations, variations of global RI events in offshore regions remain uncertain. Here, we show that compared with open oceans, where the annual RI counts do not show significant changes, offshore areas within 400 km of the coastline have experienced a significant increase in RI events, with the count tripling from 1980 to 2020. Furthermore, thermodynamic environments present more favorable conditions for this trend, and climate models show that global ocean warming has enhanced such changes. This work yields an important finding that an increasing threat of RI in coastal regions has occurred in the preceding decades, which may continue under a future warming climate.