Hurricane Idalia — the only storm to make landfall in the United States last hurricane season — caused about $3.6 billion in damage and killed a dozen people, according to a final report about the storm that was released by the National Hurricane Center this week.
The report lays out the life and demise of Idalia, including that the storm peaked at a Category 4 before weakening at landfall on Aug. 30. And while the storm directly hit a mostly remote portion of Florida’s Big Bend, it flooded areas across Florida’s west coast, including parts of the Tampa Bay area.
Idalia was far from the costliest or deadliest storm in state history. However, the report lays out the sheer power of the storm, including a 12-foot storm surge along its path.
Idalia was the third-strongest hurricane to harm Florida’s Big Bend region, behind only the 1896 Cedar Key Hurricane and Hurricane Easy in 1950.
Here are five things to know about Idalia based on the report.
1. Storm surge inundated the west coast
Idalia made landfall where the coastline is cushioned by wetlands and forests. Despite the natural barriers, Idalia’s storm surge flooded coastal towns across Taylor, Dixie and Levy counties.
Along the Steinhatchee River, close to the storm’s landfall, a water gauge recorded water rising 7 feet in just an hour.
“It just goes to show that if you don’t evacuate and you wait to evacuate until the storm surge starts, you’re probably out of luck,” said Jeff Masters, a former scientist for the National Oceanic and Atmospheric Administration.
In Tampa Bay, Idalia’s storm surge reached up to 5 feet, the report stated.
“Idalia demonstrated that Tampa Bay is highly vulnerable to storm surge,” Masters said.
Shallow water along the coast allows strong winds from hurricanes to push high amounts of water onshore. Even Idalia, which missed the area by more than 100 miles, still brought damaging surge to the area.
Nearly half the homes in St. Petersburg’s Shore Acres neighborhood were damaged by surge.
2. How Hurricane Idalia killed: rough seas and falling trees
Hurricane Idalia killed 12 people in the United States.
When a storm of Idalia’s size wallops land, hurricane experts blame the storm for both direct and indirect deaths. A direct death happens from a storm’s physical forces, like flooding or a debris strike.
Indirect deaths are harder to calculate, and usually happen from a storm’s damage. Somebody who dies from lost power, a health issue while clearing debris or contracting a disease from the storm’s floodwaters can count as an indirect death. These deaths can take experts months to determine.
Idalia directly killed eight people and indirectly killed four.
The direct deaths were all caused by rip currents and rough seas, and notably, seven happened outside Florida, according to the report.
The Florida death was a 60-year-old man who drowned in rough seas while windsurfing in Brevard County. Three others died in North Carolina, three in New Jersey and one in Delaware.
Three of the four deaths indirectly caused by Idalia were in Florida. Two people died in vehicle crashes while the storm was hitting the state. Two others, one in Florida and one in Georgia, died from falling trees during debris cleanup.
The few direct Florida deaths could be a signal that the advanced warnings helped educate residents of the incoming threats, while states to the north may not have been paying as much attention to Idalia’s risks, according to Florida state climatologist David Zierden.
3. More than $3 billion in damages
Most of the $3.6 billion in damage occurred in the Big Bend region.
Much of the damage was to the state’s agriculture industry. Strong winds blew through peanut and cotton crops, livestock and infrastructure, the report said.
The report acknowledges that had Idalia hit a more populated area, damage costs likely would have been higher.
“We were very fortunate that it did hit one of the least-populated areas of the Gulf Coast,” Masters said.
A storm surge of 12 feet could have been catastrophic for a built-up area, Masters said. Idalia’s cost, while still significant, ranks at the bottom of the country’s 50 most expensive storms.
4. How accurate was Idalia’s forecast?
Forecasters acknowledge that the storm system formed earlier than expected and that Idalia’s creation “was not particularly well forecast” in the early stages.
But as Idalia built steam, forecasters dialed in on the storm’s predicted track. Even while the storm was still south of Cuba, there was general agreement that it would land somewhere near Florida’s Big Bend region, according to a National Hurricane Center graphic depicting Idalia’s forecast tracks.
A hurricane’s intensity is usually harder to pin down.
While it was churning over the Gulf of Mexico, Idalia rapidly intensified to a Category 4 storm with an estimated peak wind intensity of more than 130 mph. But the storm made landfall during a low tide and as it was forming a new eyewall — which weakened the storm to a Category 3 — knocking down the peak storm surge.
National Hurricane Center forecasters “generally predicted the rapid intensification and weakening phases of Idalia well,” according to the report.
“As hurricane models become more sophisticated and refined, the skills of forecasting a hurricane’s path improve almost yearly,” Zierden said.
One improvement coming this year? The “cone of uncertainty” created by the National Hurricane Center is moving inland to better depict wind and flooding risks to areas outside of the immediate coastline. The experimental forecast should be ready around Aug. 15, according to the hurricane center.
5. A look ahead to next hurricane season
The hurricane center’s report comes a few months before the official start of the hurricane season on June 1. Soon, major research centers, including the hurricane center, will release outlooks for the season.
Idalia was the only landfalling storm in Florida, which is unusual. A possible reason is because this past season took place during an El Niño year, which typically suppresses hurricane activity. El Niño’s counterpart, La Niña , typically fuels it.
This season’s forecasts will likely be influenced by a possible La Niña that is expected to settle in at the peak of hurricane season.
Last week, the National Weather Service’s Climate Prediction Center said the globe is under a “La Niña watch.” By the time June rolls around, La Niña has a 55% chance of falling into place.
La Niña conditions typically fuel hurricane activity because it removes conditions that quell storm formation, like wind shear.
