One of the scariest things about Hurricane Helene — an "extremely dangerous" Category 4 hurricane barreling up the Gulf coast of Florida on its way to smack into the Big Bend area, according to the National Hurricane Center — is just how fast it spun up .
Forecasters warned over the weekend that Potential Tropical Cyclone Nine in the northern Caribbean Sea was going to be a bad one. On Tuesday morning, Sept. 24, just before 11 a.m., it developed into Tropical Storm Helene
By Wednesday morning it was Hurricane Helene . By Thursday morning, it was a Category 2 hurricane and by late afternoon it had powered up into a Category 4 hurricane with 130 mph sustained winds.
From tropical storm to Category 4 hurricane in about 64 hours. That didn't give Floridians much time to prepare, or to flee. It's called "rapid intensification" when storms quickly surge from windy to catastrophic monsters and it happened to many of the most destructive storms to hit our shores.
As global warming heats up the oceans , experts say you can expect more of these .
What is 'rapid intensification'?
According to the National Hurricane Center , "rapid intensification" is when the maximum sustained winds in a tropical cyclone increase at least 30 knots (34.5 mph) in 24 hours. That's a leap of about two categories on the Saffir-Simpson scale, which measures hurricane strength and potential damage from 1 to 5.
"Rapid intensification occurs when a tropical storm or hurricane encounters an extremely conducive environment," Colorado State University meteorologist Phil Klotzbach said in 2020. "Typically, this environment consists of very warm water, low vertical wind shear and high levels of mid-level moisture."
Out of 104 Category 3 or higher hurricanes from 1990 to 2022, 88% of them underwent rapid intensification according to a 2022 study by Klotzbach. Last year, 13 of the 37 named storms in the Atlantic and Pacific rapidly intensified.
Other conditions also can contribute to rapid intensification, such as light upper atmospheric winds under an area of high pressure, which allows a hurricane to ventilate itself and get stronger, Weather.com said.
Helene is expected to get stronger in the warmer-than-usual waters of the Gulf of Mexico, but it isn't yet known if rapid intensification will occur.
Here's a look at some storms where it did.
Hurricane Beryl broke lots of records
Last year, Hurricane Beryl changed a lot of record books .
It was the first hurricane on record to reach major hurricane status before July 1 (it hit Cat 3 on June 20), it was the first to do so that quickly before Sept. 1, and it was the earliest-forming Category 5 hurricane on record, among other things.
Beryl grew from a tropical depression with 35 mph winds into a major hurricane with 115 mph winds in under 42 hours. It ultimately made landfall three times , in Grenada, Quintana Roo and Texas, peaking at Category 5 at one point.
Just a few other notable recent storms that got very strong very quickly:
- Hurricane Laura, 2020 : From becoming a tropical depression on Aug. 20 to a tropical storm, Laura became a hurricane in the Gulf of Mexico on Aug. 26 and rapidly spun up into a Category 4 hurricane with peak winds of 150 mph before making landfall in Louisiana . Deaths: 81. Estimated damage: $23.3 billion.
- Hurricane Ida, 2021: Jumped up 65 mph in just 24 hours before it struck Louisiana as a Category 4 hurricane and rampaged across the country. Deaths: 112. Estimated damage: $75.3 billion.
- Hurricane Dorian, 2019: Dorian was the strongest hurricane to ever make landfall in the Bahamas, surging from a tropical storm into one of the most powerful Category 5 hurricanes to make landfall with 185 mph sustained winds. It stalled near Grand Bahama and stayed near that intensity for 24 hours, relentlessly pounding the area. Deaths: 84. Estimated damage: $5.1 billion.
- Hurricane Michael, 2018: Micahel was one of the strongest hurricanes to hit the continental U.S., striking Florida in Bay County as a Category 4 hurricane but not before jumping over 120 mph in three days with a peak at Category 5. Deaths: 74. Estimated damage: $25.5 billion.
- Hurricane Katrina, 2005: Tropical Storm Katrina formed on Aug. 23, 2005 and passed over South Florida as a Category 1 hurricane, weakening back to tropical storm strength. But in the warm waters of the Gulf it rapidly intensified into a Category 5 hurricane and then weakened to a high Category 3 before it devastated southeast Louisiana . Deaths: 1,392. Estimated damage: $125 billion.
- Hurricane Rita, 2005: Rita also hit Category 5 level winds in the Gulf before weakening to a Category 3 and making landfall in Louisiana, flooding communities still reeling from Katrina . Deaths: 120. Estimated damage: $18.5 billion.
Hurricane Patricia was the most powerful fast-growing storm
In 2015, Hurricane Patricia in the Pacific Ocean meandered a bit before becoming a tropical storm, and then extremely favorable conditions fed explosive intensification and it grew into a Category 5 hurricane in just 24 hours.
With maximum sustained winds of 205 mph, Patricia became the most intense tropical cyclone on record in the western hemisphere and the strongest in the world based on wind speed.
Patricia made landfall in Jalisco, Mexico , with wind speeds of 150 mph, the strongest Pacific hurricane on record until Hurricane Otis in 2023.
Contributing: Dinah Voyles Pulver, USA TODAY
This article originally appeared on Tallahassee Democrat: Hurricane Helene spun up to Category 4 in just days. What is 'rapid intensification'?
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