It’s a nightmare scenario that keeps forecasters up at night: A tropical cyclone strengthens quickly over a 24-hour period.
It happened last year close to home with Hurricane Laura, which evolved from Category 1 to a more devastating Category 4 before striking near Lake Charles, La., sweeping buildings from foundations and killing seven people with surf and falling trees.
Researchers in the latest report from the Intergovernmental Panel on Climate Change agree it’s likely that the tropical cyclones that formed over the past four decades increasingly went through such a period of rapid intensification. They also say a greater proportion of future hurricanes will very likely be Category 4 and 5.
Coastal communities need to prepare, experts say.
The trend toward a greater frequency of storms getting stronger fast may continue, according to Texas State Climatologist John Nielsen-Gammon. Unexpected high winds and storm surges can cause disaster. Strong winds leave communities powerless and storm surges kill.
But evacuating vulnerable areas requires time; doing so too hastily can be dangerous.
“That’s really the nightmare scenario for forecasters and emergency managers,” said Robert Rogers, a research meteorologist with the National Oceanic and Atmospheric Administration who studies storm intensity changes. “Imagine a tropical storm that’s approaching landfall, maybe a 55 mph tropical storm, and it undergoes rapid intensification to become a 130 mph monster at landfall. That’s really what keeps the forecasters up at night. That’s really what a lot of our effort is going toward trying to better understand.”
Area residents may not have five or six days to prepare for and evacuate from a storm, said Jeff Lindner, meteorologist for the Harris County Flood Control district.
Three-quarters of storms that struck Texas developed and hit within 60 hours, he said. Rapid intensification can add pressure to that timeline. Hurricane Humberto in 2007 famously went from tropical depression to tropical storm to hurricane in 19 hours, hitting east of High Island.
Other memorable storms intensified rapidly too: Ike’s winds in 2008 went from tropical storm-level to Category 4 in a 24-hour period when it formed, according to satellite estimates, but weakened before hitting Galveston with deadly surge. Harvey in 2017 rapidly strengthened to a Category 4 before striking near Rockport and later drenching the Houston area, unleashing catastrophic flooding.
What terrifies environmental attorney and longtime climate advocate Jim Blackburn is the scenario where people feel equipped to handle what they think is coming and are caught off guard when it becomes something else. He worries about coastal residents dying because they prepare to ride out a small storm — and a much stronger one hits.
“People have assumed or have fallen into routines based on the past,” Blackburn said, “and that’s the whole point of climate change. You cannot depend on the past to predict the future.”
I don’t really have much to add to that. Have your emergency kit stocked and ready, know what your plan will be, and hope like heck forecasting ability continues to improve. And yeah, build the Ike Dike.
Actually, I do have one more thing, as I had drafted this a few days ago: Be ready to donate to Hurricane Ida relief funds. Louisiana will need all the help it can get.