When the oceans warm, hurricanes become more frequent and increasingly intense. According to new research, this could be bad news for the New England region and not just the Caribbean and southeastern United States.

Geoscientists from the University of Massachusetts Amherst and Woods Hole Oceanographic Institute (WHOI) report that between 800 and 1700 years ago hurricane activity was much more intense in the northeast coast of what would become the United States.

The team studied sediment deposits in Cape Cod and found evidence of hurricanes more intense than anything New England has seen in recorded history. Intense storms frequently pounded the area from about 250 CE until 1150 CE.

In the current issue of Earth’s Future, a journal of the American Geophysical Union the researchers present a record of sediment deposits that show warming oceans could be very bad news for the region.

The researcher found evidence of 23 severe hurricanes that hit New England between, about once every 40 years during the period from 250 until 1150. The intensity of these storms likely rated a category three or four, similar to storms like Katrina or Hugo.

The study, the first to find historic evidence of severe hurricanes in the northeast, extends the severe weather record of the region by hundreds of years.

To find evidence for the storms, the researchers examined deposits from Salt Pond near Falmouth on Cape Cod. The pond is normally isolated from the Atlantic Ocean by a sand barrier which measures between 4.3 and 5.9 feet.

Over hundreds of years, severe storms deposited sediment over the barrier and into the pond where it settled and remained undisturbed. The team extracted a 30 foot sediment core for analysis, similar to tree ring dating.

“The study shows that our region has been prone to storms of far greater magnitude than those impacting the area over the past century. With so many more people, structures, roads and bridges in place now, we should begin to design and plan for these higher-magnitude events,” said Jon Woodruff of the University of Massachusetts at Amhurst in a statement.

A high resolution pollen diagram developed by WHOI researcher Dana MacDonald, currently a visiting scholar at UMass Amherst, helped to date the samples from the core.

“The study integrated the work of a diverse group of authors and combines a large number of hurricane reconstructions developed over the years by this group and others. The results are a comprehensive synthesis that provides insight on how major climate-forcing mechanisms influence both broad-scale Atlantic basin and regional northeastern Atlantic hurricane activity,” said MacDonald.

The sediments showed severe storm and hurricane activity from 150 to 1150 and again from 1400 to 1675. The earlier period matched previous studies that found evidence of increased storm activity during the same period in more southernly areas. The hurricane activity dropped off after 1400 and then resumed, from the Bahamas to New England until 1675.

“The large changes in the pollen reflecting clearing of the landscape and the introduction of European agricultural plants helped identify age way-points along with other dating techniques, to clearly identify hurricanes recorded in western records, especially the Colonial storms of 1635 and 1675,” said MacDonald.

We hope this study broadens our sense of what is possible and what we should expect in a warmer climate. We may need to begin planning for a category 3 hurricane landfall every decade or so rather than every 100 or 200 years. The risk may be much greater than we anticipated,” added Donnelly.

The prediction of increase hurricane activity is especially concerning in light of a recent report from the National Oceanic and Atmospheric Administration (NOAA) which predicts rising seas and increased flooding in the region in the near future. The increased sea levels could lead to increased damage if and when severe hurricanes return to the region.