TAMPA, Fla. (WFLA) — Rapid intensification is a relatively rare process that a maturing tropical cyclone can go through, in the right conditions. The National Hurricane Center defines it as “an increase in the maximum sustained winds of a tropical cyclone of at least 30 kt (35 mph) in a 24 hour period.”
The rate at which a storm can organize and strengthen is limited by multiple environmental factors. A tropical cyclone needs very warm ocean water temperatures, light winds throughout the vertical layers of the atmosphere, and moist air surrounding the storm, at the very least, according to Meteorologist Amanda Holly. There are still many unknowns about why and how certain storms go through it, making it difficult to forecast.
These three factors don’t always align which typically slows the intensification process and makes rapid intensification a rare event. However, it does happen and it seems to be happening more regularly in recent years, according to several studies.
Currently, Hurricane Ida is moving through the Gulf of Mexico where all these factors are in place. Ida is rapidly intensifying as it moves toward Louisiana. It is forecast to go from an 85 mph category 1 hurricane as of 11 a.m. Saturday morning to a category four hurricane with winds of 130 mph by 8 a.m. Sunday morning, an increase of 45 mph in less than 24 hours.
Ida has already rapidly intensified according to the definition with maximum winds at 40 mph on Friday at 2 a.m. increasing to 80 mph Saturday at 2 a.m., a jump of 40 mph in a 24-hour span.
Just last year in 2020, 10 hurricanes (out of the 13 that formed) underwent at least one rapid intensification cycle. According to NOAA, that ties the previous record number of rapidly intensifying storms set in 1995. While the minimum increase in winds is 35 mph in 24 hours to qualify, three storms in 2020 jumped at least 80 miles per hour in 24 hours, according to NASA.
Hurricane Laura was the most devastating storm in the US of 2020. It moved through the Gulf toward the Louisiana coastline and increased its winds by 55 mph in just 24 hours.
A rapid intensification cycle can be very difficult to predict with some storms undergoing a cycle without all the necessary factors. Many of the forecast models never predict these cycles before they happen, even when the atmosphere is in a prime position for it. This can leave areas scrambling to prepare for a storm that is much stronger than originally forecast making it a highly researched topic among atmospheric scientists.
The average error of a storm’s wind speeds at landfall is much larger than the average error of the landfall location. In fact, the average error on the five-day forecast cone given by the National Hurricane Center is a category above or below at any given point. Researchers at the NHC along with many scientists continue to study the processes of a strengthening hurricane to better understand how they intensify and hopefully more accurately predict how strong a storm might get.