PORTSMOUTH, R.I. — Many Common Fence Point residents understand that where they live is, as David Vallee recently put it, “ground zero as one of the most vulnerable shorelines in the state” should a Category 3 hurricane hit.

The last Category 3 hurricane to hit Rhode Island was Carol in August 1954. She hammered Common Fence Point, although the peninsula that juts into Mount Hope Bay was hardly the only section of the Ocean State to get pounded.

Vallee, hydrologist-in-charge of the National Weather Service’s Massachusetts-based Northeast River Forecast Center, said if such a powerful hurricane hit Rhode Island today, living through it would be difficult. There would also be much more damage.

The lifelong Rhode Island resident detailed the vulnerabilities of the densely populated Common Fence Point neighborhood during a Feb. 12 presentation titled “Understanding the Impact of Severe Weather on Our Community.” The event was held at the Common Fence Point community hall on Anthony Road, which is across the street from a field dedicated in 1968 to the memory of Thomas F. Kennedy that now regularly floods during storms and extreme high tides.

Coastal flooding is worsening because of sea-level rise and erosion. King tides are causing more nuisance flooding of streets, parking lots, and ball fields. Vallee said coastal erosion is “eating away our beaches,” as Rhode Island has lost 100-200 feet of beach in some parts of the state.

“The changing climate is a complex thing we are living through. It’s not just Category 3 hurricanes that do damage,” said Vallee, whose job is to study atmospheric changes and weather impacts on land and water systems. “It’s been significant enough to change our modeling. The change in how it is raining the last 50 to 60 years is pretty dramatic. We’re getting ridiculous rain events more often. Annual rainfall is increasing an inch per decade. That is huge.”

The longtime National Weather Service employee said current modeling shows 3-6 feet of sea-level rise for southern New England in the next 50-100 years. His presentation also noted that nine of the 10 warmest years on record have come since 1970 and that the coldest year in the past four decades was still warmer than the average of the 1930s.

The recent Portsmouth discussion was sponsored by the Common Fence Point Preparedness Committee. Its chairman, Jim Fogarty, said the event was designed to help “coastal residents in Common Fence Point and beyond better understand how they can begin to take action to protect themselves, homes, and communities from severe weather impacts.”

The Common Fence Point Preparedness Committee is working with the University of Rhode Island’s Coastal Resources Center and other partners, including the town of Portsmouth and the Narragansett Bay National Estuarine Research Reserve, to educate residents and encourage their involvement in efforts to protect their homes and neighborhood.

The goals of the Common Fence Point Preparedness Committee are to connect neighbors and respond to their needs, share pertinent information and resources, promote community preparedness, and build resilience.

Portsmouth and the Rhode Island School of Design are also working together to gather community input on issues of sea-level rise and storm vulnerability. The ongoing project centers on the impacts of modest levels of sea-level rise on marsh areas and infrastructure in Portsmouth neighborhoods, including Common Fence Point.

Tides already flood storm drains on Park Avenue in the Island Park neighborhood several times a year. With 3 feet of sea-level rise, Park Avenue will be gone.

As this kind of flooding becomes more frequent, it will increasingly impact road access and the viability of septic systems in low-lying areas such as Island Park and Common Fence Point, according to Peter Stempel, a provost fellow who is coordinating the RISD effort with the town of Portsmouth.

Stempel also spoke at the Feb. 12 event. He said the first step in addressing these issues is to better understand residents’ concerns. To accomplish this, the architect and his team of students are creating 3-D visualizations that allow residents to see likely near-term impacts, such as road flooding and increases in wetland areas, in context.

“This is more than a map showing flooding at some distant point in the future,” Stempel said. “We’ve connected the best models from the URI Graduate School of Oceanography with advanced 3-D visualization tools so that we can show more dimensions of what is likely to happen, such as roads that will flood regularly with modest levels of sea level rise. We want to know what people’s real concerns are now — not some distant future point.”

The event’s two main speakers pointed to bioswales, elevating critical infrastructure, using lower floors of buildings for parking, and buying out homes in problem areas as possible solutions to coastal erosion, storm surge, and nuisance flooding.

Vallee, who spoke first, said there are three options: protect; adapt; and retreat, the latter of which he admitted causes “culture shock.”

Doing nothing, however, isn’t an option, since a changing climate and relentless development are conspiring to soak the Ocean State. Vallee drew a clear link between the altered global climate and new weather norms in Rhode Island and southern New England, which he said have exposed the region’s shortsighted development and inadequate infrastructure.

He said the historic flooding of southeastern New England in 2010 showed that climate change has dramatically altered how rivers and streams are reacting to more intense and frequent precipitation. He noted that 2018 was the third-wettest year on record in southern New England and that the region’s antiquated stormwater infrastructure was designed to handle rainfall of the 1950s.

In Rhode Island, annual precipitation has increased by 12 inches since 1905, mostly during non-summer months, according to the URI/Rhode Island Sea Grant Climate Change Collaborative. In New England and New York, the frequency of 2-inch rainfalls has increased since the 1950s, and storms once considered a 1-in-100-year event have become more frequent, according to the Northeast Regional Climate Center at Cornell University.

Climate change has altered the jet stream, causing larger, more frequent, and intense multi-day rain storms, according to Vallee. He said slow-moving weather systems are clogging the atmosphere, creating intense storms that linger.

Hurricane Sandy in 2012 is the example of this atmospheric loitering. When Sandy hit Rhode Island, it was barely a tropical storm, but it hung around for so long — nearly three days and several tide cycles — that it caused plenty of damage, even though Vallee noted that the storm landed nothing more than a “sideswipe.”

But lingering storms and more frequent rains alone don’t entirely explain the increase in southern New England flooding events. It’s also about urbanization and land-use management, he said.

All of this climate-change induced precipitation and the acres and acres of impervious surface that exacerbate damaging flooding can hinder emergency services, contaminate drinking water, and increase mosquito-borne disease. It also can contaminate coastal waters with storm drain and/or wastewater treatment facility overflows, leading to the closure of beaches and shellfish harvesting areas.

“The climate is different than it used to be, especially along the coast, where sea-level rise and higher tides are playing a role,” said Vallee, noting that the atmosphere contains more water as the planet warms. “More moisture and more energy in the atmosphere is a nasty mix of ingredients.”