NARRAGANSETT — Hurricanes
bound for New England will get about 10 percent more powerful by 2100, but the
state lacks the tools to access their impacts, according to University of Rhode
Island professor Isaac Ginis.
 |
| URI's Ginis (photo by Tim Faulkner) |
Hurricanes are powered by warm water, and the predicted increase
in ocean temperatures caused by climate change is expected to make hurricane
season longer and the storms stronger in the years ahead.
“Hurricanes love warm water,” Ginis said during a July 24
climate change seminar at the University of Rhode Island.
Numerous studies and models suggest the frequency of category 4
and 5 hurricanes are expected to increase by 81 percent, while the volume of
rainfall is expected to increase 20 percent by 2100, Ginis said.
However, a key current modeling method used to measure the
impacts of hurricanes and set flood insurance maps is outdated, he said. The
federal Hazus model
mostly relies on ocean temperatures to predict damage on land. But, Ginis said,
this modeling leaves out critical atmospheric factors that hurricanes encounter
as they approach New England, such as cold fronts and the jet stream.
These local factors can make hurricanes more powerful as they
take on the characteristics of a nor’easter, he said. “That’s why they often
gain energy and intensify.”
Earlier this month, Hurricane Arthur was considered benign as it
passed to the east of New England, but the storm strengthened as it headed
north along the Gulf Stream and encountered new atmospheric conditions. Arthur then
inflicted significant damage when it made landfall in Canada’s maritime
provinces, with more rain and higher winds than expected.
“We’re lucky the storm did not undergo extra-tropical transition
when it was close to Rhode Island,” Ginis said.
Another problem with current hurricane forecasting is the public
and media fixation on the 1-5 ranking system assigned to measure hurricane
strength, he said. The ranking is primarily based on wind speeds but leaves out
other critical factors, such the height of water within a hurricane. Water
height determines the storm surge and influences coastal and inland flooding,
two factors that caused major damage in hurricanes Sandy and Katrina.
“Scientists and the forecasters hate this scale," Ginis
said. "It really does not represent the threat (from hurricanes)."
As an alternative, the National Hurricane
Center is
experimenting with detailed real-time models that monitor water height, storm
surge and flooding.
Hurricane forecasting and planning, however, used by the Federal
Emergency Management Agency (FEMA) and state planners relies on a modeling
system called SLOSH (sea, lake and overland surges from
hurricanes). SLOSH modeling began in the 1960s and doesn’t take into account
atmosheric and geographic factors that are common to the Northeast during
hurricanes.
“We do need a more robust threat and risk analysis in Rhode
Island,” Ginis said.
In order to create a better hurricane predictor, Ginis is
working with URI’s Graduate School of Oceanography on a multi-model system that
uses 3-D simulations, as well as climate-change assumptions, such as sea-level
rise, to gauge atmospheric and oceanic conditions of approaching storms. This
multi-model approach also would measure the impacts of hurricane after they
pass.
“If you are just looking at only one model you’re prone to make
several significant errors in your assessments,” he said.
This research contributes to two programs sponsored by the
National Oceanic and Atmospheric Administration (NOAA) that aim to improve
hurricane tracking, forecasting and understanding of potential impacts. The URI
group is also offering its expertise to the state Beach SAMP project
to help improve hurricane risk analysis in Rhode Island.
Grover Fugate, director of the state Coastal Resources
Management Council (CRMC), the agency overseeing the Beach SAMP, said having this
information helps cities and town better understand the risks and
prepare.
“We really need to start thinking about these practices and how
we put those in proactively, so that we can act when the storm comes,” Fugate
said.
