As thousands of people are still without power in Louisiana, thousands more up north are still dealing with damaging floodwaters from Hurricane Ida.
The storm was the strongest to hit the United States during this year’s hurricane season as it evolved from a Category 1 hurricane with winds of 85 mph to a major Category 4 hurricane with 150 mph winds in less than 24 hours.
It is just the latest storm to go through a process called rapid intensification, where sustained winds increase at least 35 mph in a 24-hour period.
“The storms that find themselves in a favorable environment and are rapidly intensifying does seem to go up since 1990,” said Michael Bell, a researcher at our nation’s leading hurricane research center at Colorado State University.
Rapid intensification occurs when there is warm ocean water, little changing wind direction in the upper atmosphere, which can kill a storm’s energy and an abundance of moisture in the air.
The National Oceanic and Atmospheric Administration (NOAA) says parts of the Gulf of Mexico are three to five degrees warmer than their average at the end of the 20th century, and the Intergovernmental Panel on Climate Change (IPCC) says human greenhouse gas emissions have caused oceans to warm faster now than at any point since the end of the Ice Age.
During the 2020 hurricane season, 10 storms rapidly intensified, some to a record degree.
Researchers at NOAA say in the 1980s, the probability of a storm rapidly intensifying was 1 in 100. Today, they are 1 in 20.
“Even though we talk about rapid intensification as a wind problem; if the storm is more intense it’s going to bring rain, wind, and surge into these coastal areas and well in-land,” said Bell.
That was seen in parts of the South and Northeast, as Hurricane Ida sustained more energy as it traveled through, a time when storms rapidly lose their energy because of a lack of warm ocean water.
New York City saw 7 inches of rain in a five-hour period, leaving cars sunken in the middle of streets, and the subway system completely flooded.
In New Jersey and Pennsylvania, tornado warnings had people sheltering underground as they waited for the storm to pass.
In a 2017 paper published in the Bulletin of the American Meteorological Society, an MIT researcher found that rapid intensification events that happen once-in-a-century, where wind speeds increase 70 mph in 24 hours, could happen every five to 10 years by 2100.
