Here’s How Hurricane Ida Was Rapidly Powered To Become A Beast


Hurricane Ida, which hit the Louisiana coast with winds of 150 miles per hour on Sunday, gained strength faster than most storms. Due to climate change, this type of rapid reinforcement is becoming more frequent as hurricanes harvest more energy from the warmer ocean water than before.

But in a summer of extreme weather, Ida’s concentration was extreme.

The storm’s maximum sustained winds as of Saturday morning were about 85 mph, making it a Category 1 hurricane, according to the National Hurricane Center’s forecast releases. Less than 24 hours later, they were 65 mph stronger, pushing Ida closer to Category 5.

The storm intensified more than the hurricane center’s forecast, which called for maximum winds to reach 140 mph. The hurricane center’s definition of rapid intensification is at least a 35 mph increase in wind speed within 24 hours. Ida grew this strong in just six hours overnight.

Climate change is part of the cause. The researchers found that the frequency of Atlantic hurricanes, which have intensified rapidly over the past four decades as ocean temperatures rise, has increased in frequency, largely because the warmer waters provide more of the energy to fuel these storms. In the 1980s, the probability of a hurricane experiencing a rapid escalation was around 1 percent. Now there is a 5% chance.

But experts who study the behavior of hurricanes said other factors play a role in Ida, such as the seasonal warming of the Gulf of Mexico, the amount of moisture in the atmosphere, and the presence or absence of winds that can affect a storm’s structure.

Currently, the Bay is extremely hot as it accumulates heat during the summer. It is this seasonal warming that also occurs in the Atlantic Ocean, which is the most active part of the hurricane season each year from mid-August to October.

But researcher Joshua Wadler of the University of Miami and the National Oceanic and Atmospheric Administration said it’s not just the Gulf’s surface temperature that matters. Hurricanes really cool the ocean as they travel, as they mix water up to about 150 feet and mix with colder water from below.

In this case, Ida has sailed over much warmer waters up to that depth. Dr. Probes sent into the water by hurricane fighters on Saturday revealed the temperature was about 30 degrees Celsius, or 86 degrees Fahrenheit, after mixing by Ida, Wadler said.

“This is at the very high end of sea surface temperatures where hurricanes experience,” he said.

NOAA researcher Chris Slocum said the storm’s path followed this warm water, which scientists call a vortex.

“Ida found the perfect path across the bay with the warmest water,” he said, and that provided plenty of energy for the storm to take off. “You could say this is a worst-case scenario.”

Dr. Slocum compared the situation to that of Katrina, which crossed a colder water column as it approached Louisiana in 2005 and weakened from Category 5 to Category 3. Ida has never encountered colder water.

“This continues the uptrend,” he said. “The only thing that will stop the condensation process is landfall,” he said.

Dr. Wadler said that vortices occur in the Gulf each year, when part of a cyclical current breaks off. And while it’s extremely difficult to associate a specific one with climate change, it’s “as profound as we’ve seen for a very long time,” he said.

Dr. While ocean temperatures are the most important, two other factors influence how much and how quickly a storm gets stronger, Slocum said.

Atmospheric humidity affects the storms that form a tropical cyclone. The more humid the air, the more these storms survive and persist. And the way these thunderstorms interact with each other can affect whether it gets stronger, especially in the eyes of the storm.

Wind shear—changes in wind speed and direction with altitude in the atmosphere—can also affect a hurricane’s structure. Dr. If the wind shear is too strong, “you can smash a storm,” Slocum said.

Forecasters of the hurricane center had been watching the wind shear closely. It was a factor that the storm entered the Gulf on Friday and gave Ida an asymmetrical structure. But the scissors broke up on Saturday, allowing the storm to spiral into a more regular shape.

The effect on wind speed can be compared to what happens to figure skaters during a spin. Skaters who keep their arms in a tight, precise position will spin faster. However, if one of their arms is extended, they will spin much more slowly.

Dr. It can be difficult to predict whether a hurricane will intensify quickly, Slocum said.

“It’s kind of a Goldilocks problem,” he said. “If one of these components is slightly broken, we won’t be able to see it.”



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