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The Threat To New England

By Joe D'Aleo
Monday, August 25, 2008

Last week we discussed why the east coast was at increased risk in this current period with a cold Pacific (negative PDO) and warm Atlantic (positive AMO) and what might happen if a CAT3 storm like 1938 repeated or, worse yet, came closer to New York City.


Another area in the northeast at special risk is southeastern New England. The bays are open to the south almost inviting a storm surge. Major surges occurred in both 1938 and 1954 with Hurricane Carol. Buzzards Bay and Cape Cod were actually hit hardest in Carol, which tracked east of the 1938 storm.

 

 

Note that the Providence are has a 51 year return frequency for CAT3 storms. The last CAT3 was 54 years ago.

 

Like New York City and Long Island, these areas are much more vulnerable today than they were in 1938 or 1954 because of the residential and commercial development that has taken place. Some of the most expensive properties in New England are on the south coast because of the appeal of the climate and ocean views.

 

 

 

Some steps have been taken to try and minimize damage from similar storms. But depending on the storm, they may or may not prevent disaster.

 

According to Maurice Spaulding an ocean engineering professor at URI in the Providence Journal (Dec, 2005)

     Providence’s Fox Point Hurricane Barrier was built to withstand a 20 1/2-foot surge. The Hurricane of 1938 sent a 15.7-foot wall of water up the Bay, and the surge from Carol in 1954 was only a foot lower.

     A storm surge of 14.7 feet would put Providence's Field's Point under water. A surge of 24 feet would put the entire  Providence waterfront underwater 

 

In Rhode Island there are vulnerable neighborhoods such as Matunuck, in South Kingstown, Misquamicut, in Westerly, and Common Fence Point, in Portsmouth, where residents would be urged to leave. They are scarcely above sea level.

 

State officials blocked redevelopment in some areas that were destroyed by the Hurricane of 1938 -- Napatree Point, in Westerly, and barrier beaches where Misquamicut and East Matunuck State beaches now stand.

 

 

After the 1938 storm, the last two storms to affect these regions were Carol in 1954 and Bob in 1991.

HURRICANE CAROL*
(CAT 3 - August 31, 1954)

On the morning of August 31, Hurricane Carol, the most destructive hurricane to strike southern New England since the Great New England Hurricane of 1938, came crashing ashore near Old Saybrook, Connecticut, leaving 65 people dead in her wake. Carol had developed in the Bahamas several days earlier, making only slow progress northward. Carol began her rapid acceleration during the evening of August 30, while passing just east of Cape Hatteras, North Carolina. Carol made landfall on eastern Long Island and southeastern Connecticut about 12 hours later, moving at over 35 mph.

Sustained winds of 80 to 100 mph roared through the eastern half of Connecticut, all of Rhode Island, and most of eastern Massachusetts. Scores of trees and miles of power lines were blown down. Strong winds also devastated crops in the region. Nearly 40 percent of apple, corn, peach, and tomato crops were ruined from eastern Connecticut to Cape Cod. Several homes along the Rhode Island shore had roofs blown completely off due to winds which gusted to over 125 mph. The strongest wind ever recorded on Block Island, Rhode Island occurred during Carol when winds gusted to 135 mph. The National Weather Service in Warwick, Rhode Island recorded sustained winds of 90 mph, with a peak gust of 105 mph. Lowest recorded pressure was at Suffolk County Airport on the south shore of Long Island with a reading of 28.36.

Hurricane Carol arrived shortly after high tide, causing widespread tidal flooding. Storm surge levels ranged from 5 to 8 feet across the west shore of Connecticut, and from 10 to 15 feet from the New London area eastward. Storm tide profiles show, as in 1938, how dramatically the tides increased just before landfall across Narragansett Bay, the Somerset, Massachusetts area and in New Bedford, Massachusetts harbor. Narragansett Bay and New Bedford harbor received the largest surge values of over 14 feet in the upper reaches of both water ways. On Narragansett Bay, just north of the South Street Station site, the surge was recorded at 14.4 feet, surpassing that of the 1938 hurricane. However, since Hurricane Carol arrived after high tide, the resulting storm tide was lower.

Coastal communities from central Connecticut eastward were devastated. Entire coastal communities were nearly wiped out in New London, Groton, and Mystic, Connecticut, as well as from Westerly to Narragansett, Rhode Island. Once again, as in the 1938 hurricane, downtown Providence, Rhode Island was flooded under 12 feet of water.

Rainfall amounts ranged from 2 to 5 inches across most of the area. The heaviest amounts, up to 6 inches, occurred in the New London, Connecticut area in the vicinity of landfall, and across extreme north central Massachusetts.

Hurricane Carol destroyed nearly 4000 homes, along with 3500 automobiles and over 3000 boats. All of Rhode Island, much of eastern Connecticut and much of eastern Massachusetts lost electrical power. In addition, as much as ninety-five percent of all phone power was interrupted in these locations.

*This information was taken from SOUTHERN NEW ENGLAND TROPICAL STORMS AND HURRICANES, A Ninety-eight Year Summary 1909-1997, by David R. Vallee and Michael R. Dion, National Weather Service, Taunton, MA.

As David and Michael note, southeastern Massachusetts was hit severely by Carol. Carol was more damaging to southeastern Massachusetts than the 1938 hurricane. Around New Bedford and Buzzards Bay, the scene was one of devastation. Tides in Buzzards Bay reached their highest known levels since records were kept. The massive storm surge swept away cottages and destroyed the many small boatyards along both ends of Buzzards Bay.

 

Along the Outer Cape, a storm surge of at least 13-feet (with 10-foot waves) created a 20-foot wall of water that swept away buildings, homes, cottages, and businesses. Weeks after the storm, piles of wreckage could be seen for miles along Route 6 in southeastern Massachusetts.

 

 

 

 

Cedar Tree Neck in Warwick has been rebuilt since 1954.

But during the last 50 years after Carol, nearly 12,000 houses have been built near the ocean along Rhode Island's south shore. Another 500 acres along Narragansett Bay have been filled in and the Bay's shoreline is jammed with houses and marinas. See Providence Journal story Changes On The Coastline Heighten Storm Danger by Peter B. Lord.

They were put to the test in hurricane Bob in 1991, but fortunately it did not quite pack the punch of 1938 or Carol.

 

HURRICANE BOB

(CAT 2 – August 19-21, 1991)

The beginnings of this tropical cyclone were along an old frontal boundary southeast of Bermuda on the 12th. By the morning of the 15th, a low was located a couple hundred miles east of the Bahamas.  By the next day, it is estimated the cyclone developed into a tropical depression 175 nm east of Nassau.  The system turned to the west and west-northwest, and developed into a tropical storm on the 16th.  The next day, a central dense overcast was noted, and Bob had become a hurricane as it turned northward.  A deep trough over the East had picked up the storm, and it accelerated northward.  Bob intensified into a major hurricane east of the Outer Banks of North Carolina, then passed over cooler shelf waters.


Weakening ensued as it approached New England, clipping the east side of Long Island.  It came ashore again over Block Island before striking Newport, Rhode Island on the afternoon of the 19th as a category 2 Hurricane.  It made a final landfall as a tropical storm late on the 19th near Rockport, Maine, later crossing Maine, New Brunswick, the Gulf of St. Lawrence, and northern Newfoundland. Below is the track of this cyclone, provided by the National Hurricane Center.
 

 

As the western tip of Bob's eye passed over Montauk Point and over Block Island, Air Force Hurricane Hunters reported a central pressure of 28.40 inches (962 mb) and sustained winds of 105-mph. Bob was weakening swiftly, and hurricane hunters reported the eye falling apart after passing over Block Island. Bob then crossed the coast near Newport, Rhode Island with a central pressure of 28.47 inches and sustained winds of 95 -100-mph. In Rhode Island,  There were also several dozen unofficial wind measurements of gusts between 100 and 120-mph across many sections of southeastern Massachusetts and east coastal Rhode Island - including a gust of 125-mph at Block Island Airport.

 

Hurricane Bob produced a storm-surge of 6 to 10-feet across the landfall area. Bob caused the worst storm surge flooding since Hurricane Donna in Rhode Island and Massachusetts. As expected, the highest surges associated with the storm occurred just to the east of the track. The U.S. Coast Guard Station at Montauk, estimated Bob had a storm-surge of 10-feet above normal at the very tip of eastern Long Island. Along the Rhode Island coast near the Newport, Bob's storm surge was estimated at 6 to 8-feet above mean tide. The highest surges were in Buzzards Bay. The track of the storm drove water up this narrow estuary where it reached an estimated 9-feet above mean tide. In Providence, the feared repeat of catastrophic flooding in Narragansett Bay was avoided by the storm's track, and at least partly, due to the Providence Hurricane Barrier. The tide against the barrier reached 6.6- feet above mean tide.

 

Heavy rain was confined to areas over and west of the storm track, to the east the hurricane force winds drove sea water spray well inland desiccating and stripping tree leaves.

 

SUMMARY

 

Southeastern New England like Long Island is especially vulnerable to a landfalling hurricane in the warm AMO Atlantic mode we have been in since 1995. So far The Gulf, Florida and the Carolinas have felt the brunt of the storms. As we discussed last week, the Atlantic determines the frequency and strength of the storms and the Pacific the areas most at risk. In the strong cold PDO mode we are in, La Ninas are more common and east coast landfalls are more likely than during El Ninos which have been more common in the warm PDO from 1977 to 1998. See the difference in the two charts of landfalls since 1950 for La Ninas versus El Ninos.

 

 

 

See also in the IRI graph how the risk of a direct or indirect landfall is highest for RI and MA than other northeastern states.

 

 

As we showed last week in the 9 years of La Ninas and cold PDO in the warm AMO mode, there have been 16 landfalling storms along the east coast, 11 were major and 9 affected the northeast.

 

Will the atmosphere’s memory of last winter and early spring’s strong La Nina be able to dominate over the recent weakening of the La Nina into neutral mode and El Nino like warming in the easternmost tropical Pacific and make this another year when the northeast gets a smashing direct hit or will the inevitable be postponed yet again?

 

Most years by the way when storms hit, had a wetter than normal summer or months in summer, certainly the case this summer. However the trough in the east and central that has dominated and made it so wet has recently given way to ridging and a series of cut-of lows pushing through the northeast which would likely deflect most threatening systems out before they reach the northeast. A system would have to be timed just right to find a slot between troughs.  

 

If we are lucky this year, and believe me I hope we are, having personally been lucky to survive Carol as a small boy on Long Island Sound when my beach house had water up the middle of the first floor, we are at special risk as long as the Atlantic is warm and Pacific is cold, which might be a decade or more. A major CAT 3 hit on NYC could be a $100 B storm, a direct hit CAT 3 on southeastern New England at high tide, could be a $50 billion dollar plus storm.

 

Given that roughly 80% of the region's population has never experienced a major hurricane adds the issues of potential apathy or confusion. Especially since the big ones are often moving very fast and provide little time to take protective measures.   

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