Forecast is for fewer hurricanes this year
Storm surge. Hurricane force winds. Widespread flooding.
Those are some of the terms becoming familiar to Americans since last year’s catastrophic 2017 hurricane season, when storm after storm smashed into the nation’s coasts. Lucky for Rhode Islanders and those living elsewhere on the Atlantic seaboard, 2018’s hurricane outlook doesn’t look nearly as bad, but there’s no telling what a climate change filled future could bring to little Rhody.
“It’s looking to be a near-normal outlook,” said Lenore Torreia, a meteorologist with the National Weather Service station based in Norton, Mass. “We’re expecting 10 to 16 named storms.”
The NWS works with the National Oceanic and Atmospheric Administration to come up with a seasonal hurricane outlook every year.
This year’s report, published in late May, takes into account predicted ocean temperatures, the possibility of an El Nino or La Nina weather pattern, as well as the forecasted amount of upper atmosphere wind shear. Ocean temperatures and wind shear in the mid-Atlantic, where most landfall hurricanes form, is forecasted to be near average. That news makes for a weaker predicted overall hurricane season, and good news for people up and down the East Coast.
NOAA predicts there to be, on average, 12 named storms, 6 hurricanes, and 3 major hurricanes this year. That’s a big difference compared to last hurricane season, when there were 17 named storms, 10 hurricanes, and 6 major hurricanes, including the devastating storms Maria, Irma, and Harvey.
So far this season, which started May 25 with the formation of Subtropical Storm Alberto, there have been three hurricanes, none of which have caused extensive damage in the United States. By this time last year there had already been six named storms, according to NOAA records.
How do these storms form?
“We still don’t know exactly how they form,” said Isaac Ginis, a professor of oceanography at the Graduate School of Oceanography at the University of Rhode Island. “In the Atlantic region they often form off of Africa, and in the Caribbean often from thunderstorms.”
Ginis said tropical waves off of Africa, also known as tropical disturbances, are areas of mild thunderstorm activity, relatively innocent compared to the hurricanes they might one day become.
Some tropical waves stay unorganized, drifting away into the Atlantic, but others develop, and if conditions are just right, they start to spin, take in more air, and grow, becoming a tropical depression.
“What exactly triggers the spin is not clear yet,” said Ginis. “Once we see the spin it’s a sign of a tropical storm.”
For the storm to grow the ocean water has to be warm, at least 80 degrees according to Ginis, to ensure water evaporates upward to grow clouds and powerful winds.
Once enough convection is occurring, the storm becomes an engine, with the low pressure caused by the sucking of warm air upwards drawing more moisture into the center. This becomes a vicious cycle, driving high winds, and once those winds pass 39 mph the tropical depression becomes a tropical storm and is given a name.
At that point, depending on the temperature of the water and the amount of wind shear, the tropical storm can quickly turn into a hurricane, feeding on warm air and water. Once wind speed is over 75 mph, the tropical storm is dubbed a Category 1 hurricane. The worst hurricanes, like Hurricane Irma and Maria last year, can have wind speeds in excess of 155 mph.
It’s not often that Rhode Island’s been hit by hurricanes. The worst storms in Rhode Island history were in 1938 and 1954. In 1938 the Great New England Hurricane took Connecticut and Rhode Island by surprise. In a time before satellites and instant communication, the storm struck with no warning on September 21, leading to the deaths of hundreds of Rhode Islanders, and nearly 14 feet of water in downtown Providence.
That storm was followed by Hurricane Carol in 1954, which, as recorded by the National Weather Service, had maximum winds of 90 mph and caused over 14 feet of flooding in Providence.
In more recent times Superstorm Sandy in 2012 and Hurricane Irene in 2011 brought a threat to New England, but other than widespread power outages, Rhode Island dodged the bullet.
But that might change soon.
Climate change cause for worry?
Ginis certainly thinks so.
“That is one way climate change will affect hurricanes in the future is the warming of the oceans,” said Ginis. “Based off of our simulations, we think hurricanes will be more intense in the future. Some simulations predict that there will be fewer storms, but those storms that do form will be stronger.”
Ginis went on to say that that prediction, less but stronger storms, is particularly concerning because damage from hurricanes increases exponentially with the wind speed. A Category 3 storm does a lot more damage that a Category 1.
There are other concern connected with hurricanes and climate change.
Ginis mentioned sea level rise, combined with hurricane storm surge, could lead to greater chance of flooding, and that the warmer air due to our warming planet can hold more water, leading to greater rainfall. Increased rainfall could lead to inland flooding, on top of the storm surge threat.
“In New England this increased rainfall is a particular concern because we have shorter rivers that can hold less water and contribute to inland flooding on top of seaside flooding,” said Ginis.
Ginis is the lead principal investigator for a research group, funded by the Department of Homeland Security Coastal Resilience Center, which is modeling the way hurricanes could cause inland flooding.
His group, called Modeling the Combined Coastal and Inland Flooding from High Impact Hurricanes, created a hypothetical hurricane in models, Hurricane Rhody, which is a possible worst case scenario for Rhode Island.
Hurricane Rhody hits fast and hard, takes a loop, and returns to Rhode Island to dump more rain. In total, Providence could see 14 feet of flooding downtown, even with the hurricane barrier, due to inland flooding.
“We should not just rely on past historic events,” said Ginis. “Now we can rely on computer models to create situations so we can prepare for the future. We cannot convince ourselves that we are prepared, because we are not.”
The simulation was used as a 4-day training exercise for the Rhode Island Emergency Management Agency as well as the National Weather Service, to prepare them for a worst case disaster.
Sen. Sheldon Whitehouse has strong feelings about the presence and importance of climate change. Every week in the Senate chamber Whitehouse delivers a speech on climate change, titled “Time to Wake Up.” In one speech from November 2017, Whitehouse said, “A typical Atlantic hurricane season used to generate roughly six hurricanes, three of which reached category 3 or higher. That was then. Typical is no longer typical. During August of 2017, this hurricane highway… reached 9 degrees Fahrenheit hotter than the 30-year average. “This exceptional warming supercharged storms into hurricanes bearing catastrophic damage.” Whitehouse sees climate change contributing to greater and stronger storms in the Atlantic. To try and adapt to the effects of such storms Whitehouse wrote legislation that was later passed into law, to provide funds for coastal communities to fight the effects of climate change, whether that be stronger storms or rising seas. Called the National Coastal Resilience Fund, the program will invest up to $30 million in natural improvements to coast areas, according to a press release. “Senator Kennedy and I designed this fund to help those living and working along the coast address the challenges they face as the consequences of climate change come ashore,” said Whitehouse in a statement, referring to Sen. John Kennedy of Louisiana, a legislator hailing from a state battered by hurricanes and rising waters. “I’m excited to see the innovative projects submitted for consideration by Rhode Island universities, nonprofits, and local governments to protect our coastal economy and way of life from floods, storms, and rising seas.”
“I am extremely concerned about how the state is prepared for dealing with a big storm, so the more information we can to the public, the better,” said Ginis.
And so we wait, and prepare, for the next big one.