Tuesday marked the official start of the Atlantic hurricane season, which federal meteorologists predict will be “above normal” in terms of storm activity, although not as intense as the 2020 season.
According to their forecasts, there’s a 60 percent probability that this year will see 13 to 20 named storms, of which about half will become hurricanes and three to five will become major hurricanes, those classified as category 3 or above.
“Although (National Oceanic and Atmospheric Administration) scientists don’t expect this season to be as busy as last year, it only takes one storm to devastate a community,” said Acting NOAA administrator Ben Friedman in a statement on the prediction this May.
The Virginia Department of Emergency Management is preparing for hurricane season as usual, although the ongoing COVID-19 pandemic has necessitated certain “precautions, particularly if sheltering is needed as we still have a portion of our population that cannot receive a vaccine — such as young children, or choose not to be vaccinated,” communications staff for the agency said.
So what’s normal?
What exactly is “normal” when it comes to hurricanes is undergoing some significant changes.
This spring, as part of a review conducted every decade, NOAA nudged up its baselines for what constitutes an average Atlantic hurricane season, from 12 named storms, six hurricanes and three major hurricanes to 14 named storms, seven hurricanes and three major hurricanes.
Also potentially in flux: the start of the season. Although historically the opening date has been June 1, meteorologists at NOAA’s National Hurricane Center this winter mulled pushing back the start to May 15 in light of an increasing number of pre-season storms. While the idea wasn’t adopted, the center did begin sending out tropical weather bulletins on May 15 ahead of the traditional schedule.
The earlier start isn’t off the table. This year a team of meteorologists will examine the “need for, and potential ramifications of, potentially moving the beginning of the hurricane season to May 15,” said Dennis Feltgen, a National Hurricane Center meteorologist and public affairs officer in an email. Ultimately the decision will be up to the member countries of the World Meteorological Organization’s Region IV, which includes North America, Central America and the Caribbean.
Uncertainty is a hallmark of hurricane planning and preparedness, said Joshua Behr, an Old Dominion University professor who works with the school’s Institute for Coastal Adaptation and Resilience and has done extensive research and modeling on hurricane preparation, particularly in the Hampton Roads region.
“The question is, ‘How much uncertainty?’” he said. “We’re not even certain how long the hurricane season should be.”
Climate change and hurricanes
Hurricanes — or at least the threat of them — have long been a regular if unwelcome staple of Virginia’s calendar. Asked about storms that have affected Virginia over the past decade, the Department of Emergency Management sent a list of 18 “notable” tropical storms and hurricanes, from Irene in August 2011 to Zeta in October 2020.
Damage from these tempests vary. Irene produced the fourth-highest storm surge on record for the Sewells Point tide gauge in Norfolk, which has been collecting data since 1927. Hurricane Florence in August-September 2018 produced 11 tornadoes and left three dead. Others produce few significant effects, passing through with only heavy rainfall and moderate storm surge.
What appears to be new, however, is how hurricanes are behaving overall: how intense they are, how rapidly they move, and how much rainfall they produce.
Jeremy Hoffman, chief scientist at the Science Museum of Virginia in Richmond, said the most recent research “suggests that climate change is probably increasing the intensity of tropical cyclones through warming at the ocean surface.”
“The hurricane derives its strength from the temperature of the water over which it’s forming,” he said.
Sea level rise — which in the Hampton Roads region is a result of both climate change and land subsidence — is also “amplifying” storm surges, while “increased water vapor in the atmosphere is probably driving heavier rainfall, creating the conditions for inland flooding,” he noted.
These effects aren’t unique to the Virginia coast, although Hampton Roads may be particularly at risk due to the rapid rate of sea level rise it’s experiencing. Scientists around the globe have pinpointed the connections between climate change and hurricane trends.
“High-intensity hurricanes … are expected to become more common in the future due to climate change,” found the U.S. Fourth National Climate Assessment released by President Donald Trump’s administration in November 2018. An overview of current research by NOAA’s Geophysical Fluid Dynamics Laboratory at Princeton University found that “it is likely that greenhouse warming will cause hurricanes in the coming century to be more intense globally and have higher rainfall rates than present-day hurricanes.”
That doesn’t mean there will be a higher total number of hurricanes. Studies have largely shown increases in the frequency of Category 3 and higher hurricanes, but not changes in overall incidence, said Hoffman.
“Think of it like climate change loading the dice for more intense storms overall, but not necessarily more of them,” he wrote in an email.
Different populations, different risks
For emergency planners, the scenario isn’t all doom and gloom.
Even as climate change has introduced new uncertainties, hurricane tracking “has made leaps and bounds in the last 20 years and especially the last 10 years,” said Behr. “Our science is getting better at predicting those paths and knowing where they’re going to make landfall.”
Hurricanes don’t just hit locations differently, however. They also affect populations differently, complicating the task emergency managers face when storms sweep through a region.
“I see storms as equity issues because there’s such disparity in how storms impact us and how we recover from storms,” said Behr. “We have a pretty good idea of who’s going to be hit hardest.”
According to the researcher, not only do low-income populations, those without an extensive family or social network and those who are “medically fragile” tend to be hit hardest by storms, but they also tend to have some of the lowest evacuation and sheltering rates.
Surveys and focus groups conducted in the Hampton Roads region have teased out a variety of reasons for those trends that largely stem from how different populations perceive the risks of evacuation versus the risks of staying in place.
People with less job security or who are living paycheck to paycheck tend to be more reluctant to evacuate and risk losing their job or spending money for fuel and shelter if it isn’t absolutely necessary, said Behr. Others want to be sure to be on hand for when the storm passes and there’s money to be made from repair and recovery jobs. He recalled one resident of the geographically vulnerable Willoughby Spit in Virginia Beach citing a potential $200 in cash they could make from cleaning up a neighbor’s yard after a hurricane as a reason not to evacuate.
“To that person the prospect of having $200 cash for doing the yard cleanup was enough incentive,” he said.
Then there’s the people whose risk assessments are colored by doubt: conspiracy theorists who believe storm warnings are an attempt by businesses to sell more products or skeptics who believe “that the risk is being ginned up to a higher level to get people to mobilize.”
Ironically, a lack of disaster can fuel that mistrust.
“We’ve had a number of near misses, and each time there’s a near miss, the propensity to evacuate for the next storm drops,” said Behr.