Climate change is strengthening the severity and frequency of storms, and 2020 is on track for another active hurricane season — the fifth consecutive such season, if the prediction comes to pass.
Indications so far seem to back up that prognostication. In June, Hurricane Cristobal beacame the earliest occurrence of a third named system in the Atlantic basin during any hurricane season in recorded history, and went on to wreak havoc on Gulf Coast.
Warmer-than-average sea surface temperatures in the tropical Atlantic Ocean and Caribbean Sea, coupled with reduced vertical wind shear, weaker tropical Atlantic trade winds, and an enhanced West African monsoon, all increase the likelihood for an above-normal Atlantic hurricane season, according to the National Oceanic and Atmospheric Administration.
Those conditions are coming on top of the effects of climate change. Warming waters and rising sea levels create additional opportunities for intensified winds in tropical cyclones and larger storm surges, potentially culminating in multiple hazards in areas that have not seen such threats in the past.
“Definitely, the climate has impacts on hurricanes,” says Richard “Ricky” Rood, professor of climate and space sciences and engineering at the University of Michigan in Ann Arbor. “There is no one impact, there are many types of impacts.”
Some experts say the increasing threat of several hazards that might be associated with a single storm, or a storm on top of another catastrophe — such as a pandemic — creates the need for clearer warnings. “Generally, we don’t have strategies for how you message for multiple hazards like this,” says Susan Jasko, a senior researcher at the University of Alabama who works with weather and emergency management entities.
Intensifying Seasons, Storms
NOAA’s Climate Prediction Center is forecasting as many as 19 named storms. Of those, NOAA says, between six and 10 could become hurricanes with winds 74 mph or higher, including three to six major hurricanes — category 3, 4 or 5 with winds of 111 mph or higher.
NOAA scientists, in conjunction with University of Wisconsin, studied satellite images from the past 40 years and concluded that climate change has strengthened wind speeds in hurricanes, typhoons and cyclones around the world. They concluded that storms are about 8 percent more likely to be a major hurricane this decade compared to the past decade.
Aside from wind damage associated with these storms, sea-level rise and extreme rain increase the potential for storm-surge damage and flooding, Rood says. In addition, Rood says, rising sea temperatures give more energy to drive hurricanes, and warmer air means more evaporation from the ocean, resulting in more potential for rain and flooding.
This season’s forecast has three important ingredients for hurricanes: a lot of warm water, the ideal wind shear and waves caused by the scorching Sahara summer that propagate to the east, causing a spinning effect.
“You have this unique aspect of the Sahara in that it gets very hot, even hotter than the equator to the south, and that temperature grading starts the genesis for that wave,” Rood says. “The prediction of hurricane season is because of very warm conditions, weak winds — low wind shear — and also the ideal state for these African easterly winds to exist.”
The ocean is increasing its surface area as sea levels rise, a fact that some experts say elongates the hurricane season in addition to making it more severe. “Those warm waters are creeping more toward spring and later into the autumn,” Rood says. “I think it’s hard to say there’s not a climate signal related to this.”
One result of the changes is that the Federal Emergency Management Agency’s recently adjusted flood zones have been expanded more than in the past, says Jamy Madeja, an attorney who represents the Massachusetts Marine Trades Association. “FEMA doesn’t do them frequently, so when they do, we’re seeing more dramatic changes,” Madeja says. “What used to be a hundred-year event is now a 10-year event.”
FEMA’s broad flood zones don’t take into account specific locations, so some operators have appealed their new designations. “You can get your flood zone made more precise, but you have to do that with engineers and with data that show it’s not an accurate flood zone,” Madeja says. “Then you have to appeal to FEMA, and it involves working with the town. The town has to agree to adopt or amend the flood maps, and there’s a whole public commentary process.”
In the meantime, some marinas are working to elevate and comply with new building codes in order to qualify for insurance, Madeja says. The insurers are watching trends not only in hurricane season, but also in multiple East Coast cities regularly experiencing flooding outside of storm events, Rood says.
“You’re seeing nuisance flooding from high tide many, many more days per year than you did 20 or 30 years ago,” Rood says. “When you get even a little bit of wind, or you get these winter nor’easters, they’ll have more storm surge associated with them because the sea level is higher. That’s just the most definitive climate signal.”
Another increasingly loud signal is strong storms showing up in unusual places. After Hurricane Andrew, South Florida changed building codes to withstand severe storms, but those changes weren’t made on the northern Gulf Coast, Rood says, in part because no category 5 hurricanes had ever made landfall there. So, when Hurricane Michael hit near Mexico Beach in 2018, residents and buildings weren’t prepared.
“That’s not necessarily just climate change, but I think the point about being prepared for more intense storms is one of the lessons we need to be learning now,” Rood says. “It’s very likely you’re going to see more intense storms in places you have not seen them before.”
That reality adds complexity to the already difficult task of warning people about events, particularly when threats stack up on one another or are unusual in certain areas. “People get used to their patterns,” says Jasko, whose work includes researching Hurricane Michael, which behaved atypically — getting bigger and stronger as it moved on land, causing the flood and wind effects to radiate farther inland than usual.
“Even though people in its path were used to hearing about storms, they were shocked by the consequences because it behaved in way that hurricanes didn’t usually behave,” Jasko says. “People can’t imagine something when don’t live with that threat, just like they can’t comprehend what it’s like to live in a city that’s being bombed every day.”
Jasko, who is originally from New Jersey, remembers watching Hurricane Irene on radar in 2011 because she was worried about her friends. Despite mandatory evacuations ordered for parts of the Jersey Shore, Irene teetered, and flooding wasn’t as severe as predicted. A year later, some residents who had evacuated ignored warnings about Hurricane Sandy, which proved devastating for the region.
Hurricane Sandy — technically a hybrid of two storm systems when it hit the Northeast, earning it the nickname “Frankenstorm” — hit during a high tide and full moon, causing flooding in parts of New York City, Brooklyn and Staten Island, as well as areas along the Jersey Shore. Breaks in gas lines caused fires in several areas, prompting explosions. “Boom, this entire neighborhood goes up in flames,” Jasko says. “It’s the middle of a freaking hurricane. Who’s worried about fire?”
Those are the types of situations Jasko studies to discover ways to help people be more prepared and heed warnings that are sometimes ambiguous. The word “watch is more dramatic than warning, but that’s not something you have to engage with very often,” Jasko says. “Most of us need another trigger to pull something out of our long-term memory.”
The National Weather Service is hiring and issuing grants to social scientists to learn more about how the human brain works in these situations, including how people react to language in different communities that, say, watch diferent news channels. “Not that data isn’t important,” Jasko says. “It’s crucial. But it doesn’t get at the problem of, what good is the information that we learn if we can’t communicate it to people?”
The coronavirus pandemic takes potential complications to another level, especially as many government agencies have employees working from home, have furloughed workers and, in some cases, have been operating with smaller budgets and staffs from the outset.
Officials at both FEMA and the Florida Division of Emergency Management couldn’t accommodate interview requests early in the hurricane season, but a FEMA spokesman says agency has already responded to severe weather during the pandemic, including “devastating tornadoes” in the Southeast.
The agency issued updated hurricane preparedness guidelines asking people to check Center for Disease Control and Prevention guidelines before going to a group shelter, and reminding them to bring things like hand sanitizer and disinfecting wipes if they have to evacuate. Florida officials are reaching out to hotels, trying to create socially distanced shelters for the upcoming hurricane season, and are asking residents to be aware of their evacuation zone, as well as their home’s overall condition to withstand a storm.
The process of assessing threats, changing response protocols and adapting warnings is more difficult at a time when many scientific agencies have been scaled back, Jasko says. “We need to go into the 2.0 version of becoming a weather-ready nation,” Jasko says. “The readiness can’t only come from these hubs of professional activity like Weather Service and emergency managers. It’s got to be from ground up so it’s community embraced and community lived.”
This article was originally published in the July 2020 issue.