Hurricanes may pack more storm surge, rainfall and wind due to climate change – Florida Today
Watch the effect Hurricane Michael winds have on these tall trees as the category 4 storm hits Panama City Beach, Florida, on Oct. 10, 2018. Video by a Rick Neale, FLORIDA TODAY Rick Neale, FLORIDA TODAY
Matthew in 2016. Irma in 2017. And Michael in October.
Major hurricanes punished the Sunshine State the past three seasons. Those three monstrous storms battered Florida’s East Coast, Gulf Coast, Panhandle and Keys, accounting for more than 200 deaths and $85 billion in damages across the continental U.S.
Is this an omen of the future?
Climate scientists fear man-made global warming will spawn stronger hurricanes, packing heavier rainfall, higher storm surge and greater winds.
“There’s plenty of evidence now in the literature that indicates these big weather events — these mesoscale systems in the Midwest and tropical cyclones — are all becoming wetter. And that is an issue,” said Steven Lazarus, a Florida Institute of Technology ocean engineering and marine sciences professor.
“They’re dumping more rain. And they will continue to do so,” Lazarus said.
The National Oceanic and Atmospheric Administration’s Geophysical Fluid Dynamics Lab warns of the following consequences by the late 21st century:
• Sea level rise should cause higher storm surge levels. “That’s setting the stage for higher damage from any given storm,” said Tom Knutson, a NOAA research meteorologist.
• Tropical cyclones will likely generate more rainfall. NOAA computer models project rainfall rate increases of 10% to 15% within about a 100-km radius if global temperatures increase 2 degrees Celsius.
“The warmer atmosphere typically will be holding more water vapor. And so, that provides more water vapor for these hurricanes to converge and create these massive rainfall amounts,” Knutson said.
• Tropical cyclone intensities will likely increase. This boost could reach up to 10% with a 2-degree Celsius global warming, increasing storms’ destructive potential.
• More hurricanes will likely strengthen to Category 4 and Category 5 levels.
Knutson cautioned that it is more difficult to detect human-caused signals in hurricanes that by simply measuring global mean temperatures. Climate change has not impacted the frequency of U.S. landfalling hurricanes, he added.
On a related front, a study published last week in Scientific Reports determined that increased greenhouse gas emissions could reduce vertical wind shear along the U.S. East Coast by 2070-99. Vertical wind shear acts as a natural barrier, thwarting hurricane intensification.
“Coupled with the robust warming of the ocean surface temperature in the future, it is likely that the U.S. East Coast will experience unprecedented hurricane intensification in the future, causing even greater threats to the coastal community,” the authors wrote.
From 1963-2012, water accounted for nearly 90% of direct deaths from U.S. tropical cyclones, the National Hurricane Center reports. Storm surge accounted for 49%, followed by rain (27%), surf (6%) and offshore deaths (6%).
In 2017-18, Hurricanes Harvey, Florence and Lane shattered state rainfall records in Texas (61 inches), North Carolina (36 inches), South Carolina (24 inches) and Hawaii (52 inches).
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“The last couple seasons, we’re setting state records when it comes to rainfall — independent of the actual wind. When we go forward, water’s what kills,” Ken Graham, National Hurricane Center director, said during an April webinar.
Lazarus concurred. In 2012, Superstorm Sandy’s storm surge reached 14 feet above a mean water mark at Battery Park in New York, shattering the previous record by 4.4 feet, the National Hurricane Center reported. Water records at Battery Park date to 1920 — and because of global warming, sea level has risen 9 inches since 1950.
“The same storm 100 years ago is going to push a foot less water onto the coasts of New Jersey and New York, all things being equal. I think that’s a pretty important point,” Lazarus said.
USA TODAY’s drone fleet shows the devastation in Mexico Beach, Florida in the wake of Hurricane Michael. Maureen Kenyon and Ricardo Rolon, TC PALM
The 2019 Atlantic hurricane season kicks off Saturday, June 1 and lasts through Nov. 30.
Last week, NOAA predicted nine to 15 named storms will form this season, including four to eight hurricanes (sustained winds of 74 mph or higher). Two to four of those may strengthen into major hurricanes (sustained winds of 111 mph or higher).
An average Atlantic hurricane season produces 12 named storms, including six hurricanes. Three of those grow into major hurricanes, clocking in at Category 3, 4 or 5.
El Niño’s wind shear may reduce the intensity of this hurricane season. But on the other hand, forecasters predict above-average sea-surface temperatures in the tropical Atlantic Ocean and Caribbean Sea and an enhanced west African monsoon — both of which are favorable for hurricane formation.
Phil Klotzbach, a Colorado State University meteorologist, is one of the nation’s foremost hurricane forecasters. During a May 15 Governor’s Hurricane Conference speech in West Palm Beach, he warned of creeping incremental sea-level increases.
“That seems innocuous enough if you’re at 5,000 feet. But if you’re at sea level and you get 6 inches more sea level rise, that can mean a lot more inundation from these storms in the future,” he said.
Klotzbach pointed out that the population of Atlantic states has doubled since 1940, from roughly 50 million to 100 million. Likewise, population in the Gulf Coast states tripled, from about 20 million to 60 million.
Illustrating his point, Klotzbach displayed a 1926 photograph of the scarcely inhabited Miami shoreline. The Great Miami hurricane struck that September as a Category 4 storm, killing 372 people and injuring more than 6,000. Klotzbach showed a modern photo of Miami Beach — with wall-to-wall condominiums cramming the coastline.
“We as humans can make storms better or worse, in terms of impact, that have nothing to do with CO2,” Klotzbach said.
Lazarus said urbanization will worsen the impact of future hurricanes on the Space Coast.
“We build, build, build, build, build — and all of this pavement and surfaces are not very porous. The water has nowhere to go. I’m watching my neighborhood in Melbourne flooding worse with these storms over the years,” Lazarus said.
“We’re getting more flooding with less water, which is kind of disturbing,” he said.
John Scott, Brevard County Emergency Management operations coordinator, encouraged residents to prepare for hurricanes during a May 21 Cocoa City Hall workshop. That includes steps as simple as transferring important paperwork from a bulky filing cabinet onto a thumb drive.
“If your plan is in your head, it’s just an idea. If you write it down, it’s an actual plan,” Scott told the audience.
“And that’s a big deal. Because if you write something down, you’re more likely to do it,” he said.
Stay informed this hurricane season
• Follow @BrevardEOC on Twitter.
• Like Brevard County Emergency Management on Facebook.
• Text BREVARDEOC to 888777 to receive text message updates.
• During storms, call 211 to reach a community information hotline.
Neale is the South Brevard watchdog reporter at FLORIDA TODAY.
Contact Neale at 321-242-3638 or firstname.lastname@example.org. Twitter: @RickNeale1
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