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History of The Perfect Storm
Late October and November are months with weather in rapid transition in the eastern U.S. To the west, large fresh cold air masses from Canada begin to envelope the Midwest on a regular basis. To the east, the Atlantic Ocean is slower to lose its stored summer heat than the continent, and hurricanes sometimes form over the warm waters. The contrast between two very dissimilar air masses often results in massive storms just offshore of North America. These tempests, called "Nor'easters" in the Atlantic states, have sunk many ocean vessels, and this storm lived up to the reputation of being severe.
On October 28, 1991, a extratropical cyclone developed along a cold front which had moved off the Northeast coast of the U.S.
By 1800 UTC, this low was located a few hundred miles east of the coast of Nova Scotia. With strong upper air support, the low rapidly deepened and became the dominant weather feature in the Western Atlantic. Hurricane Grace, which had formed on October 27 from a pre-existing subtropical storm and was initially moving northwestward, made a hairpin turn to the east in response to the strong, westerly deep-layer mean flow on the southern flank of the developing extratropical low. Grace was a large system and it was already generating large swells ranging in size from about 15 feet offshore of North Carolina to about 10 feet near the Florida coastline.
As the low pressure continued to deepen on October 29, Grace became only a secondary contributor to the phenomenal sea conditions which developed over the Western Atlantic during the next few days. At 1800 UTC on the 29th, the vigorous cold front from the extratropical low undercut and quickly destroyed Grace's low level circulation east of Bermuda. The remnant mid- and upper-level moisture from Grace became caught up in the outer part of the extratropical storm center's circulation, far from the storm's center. By the next day these remnants had become indistinguishable. The center of the extratropical low drifted southeastward and then southwestward, deepening all the time. It reached peak intensity of 972 mb and maximum sustained winds of 60 knots at 1200 UTC on October 30, when it was located about 340 n mi south of Halifax, Nova Scotia (See Event Discussion image above). After reaching peak intensity on October 30, the low retrograded southwestward on October 31, and then southward as the central pressure rose to about 998 mb by 0000 UTC on November 1.
65 Knot Winds/ 39 Foot Wave Heights
During the early phase of the storm's history, a strong high pressure center extended from the Gulf of Mexico northeastward along the Appalachians into Greenland. Strong winds were generated from the tight pressure gradient between a strong high pressure center in eastern Canada (1043 mb) and the surface low. Phenomenal seas and strong winds and waves along the eastern U.S. coastline occurred at this time. Several vessels passed close to the extratropical storm center on October 30 and reported winds of 50-60 knots. NOAA buoy 44011 located at 41.1 degrees N, 66.6 degrees W reported maximum sustained winds of 49 kt with gusts to 65 kt and a significant wave height of 39 feet near 1500 UTC. Buoy 44008 located at 40.5 degrees N, 69.5 degrees W reported maximum sustained winds of 53 kt with gusts to 63kt and a significant wave height of 31 feet near
0000 UTC on October 31. Other unsubstantiated observations reported winds and waves considerably higher.
North Carolina's coast was lashed with occasional winds of 35 to 45 mph for five consecutive days. In New England on October 30-31, wind gusts of above hurricane force pounded the Massachusetts coastline. Representative peak gusts included: 78 mph at Chatham NWS, 74 mph at Thatcher Island, 68 mph at Marblehead, 64 mph at Blue Hill Observatory (all in Massachusetts) and 63 mph at Newport, RI. Even more damaging were the heavy surf and coastal flooding caused by the tremendous seas and high tides caused by the long overwater fetch length and duration of the storm. Waves 10 to 30 feet high were common from North Carolina to Nova Scotia. High tides pushed to from three to seven feet above normal. In New Jersey, the greatest tidal departures of winter storms of record occurred during this event, with tide heights exceeded only by the Great Atlantic Hurricane of 1944.
In Delaware, Maryland, and Virginia, the highest water levels were comparable to those of the nor'easter of March, 1962. A
record high tide of 7.8 feet occurred at Ocean City, MD on the 30th, which eclipsed the old record of 7.5 feet recorded during the March 1962 storm. In Massachusetts, 25-foot waves reached the shoreline atop high tides already 4 feet above normal. At Boston, the tide reached 14.1 feet above mean low water or about 1 foot less than the tides associated with the "Blizzard of 1978." Elsewhere treacherous swells, surf, and associated coastal flooding occurred along portions of the Atlantic shoreline extending from Puerto Rico and the Dominican Republic, to the Bahamas, along the U.S. and Canada and in Bermuda.
Widespread Extensive Damage
A state by state damage summary reveals the widespread and extensive damage caused by the storm and accompanying seas.
Beach erosion and coastal flooding was severe and widespread, even causing damage to lighthouses. Hundreds of homes and businesses were either knocked from their foundations or simply disappeared. Sea walls, boardwalks, bulkheads, and piers were reduced to rubble over a wide area. Numerous small boats were sunk at their berths and thousands of lobster traps were destroyed. Flooding was extensive invading homes and closing roads and airports. Former President Bush's home in Kennebunkport, ME suffered damage as windows were blown out, water flooded the building, and some structural damage also occurred. Even inland areas suffered major damage. The Hudson, Hackensack, and Passaic Rivers all experienced tidal flooding, and high winds brought down utility poles, lines, tree limbs, and signs in several states.
The most extensive damage occurred in New England where federal disaster areas were declared for seven counties in Massachusetts, five in Maine, and one in New Hampshire. Off Staten Island, two men were drowned when their boat capsized.
Other fatalities occurred when a man fishing from a bridge was either blown or swept off in New York and a fisherman was
swept off the rocks at Narrangansett, RI by heavy surf. Offshore, six lives were lost when the Andrea Gail, a swordfishing boat, sank. Total damage in the Halloween Storm, as it came to be known because of its date, was in the hundreds of millions ofdollars.
Bizarre End to the Halloween Storm
The southward motion of the cyclone on October 31 had brought the storm over a section of the Gulfstream with sea surface temperatures near 26 degrees C (80 degrees F). Convection began increasing in bands near the center and it is estimated that subtropical characteristics were acquired at 1800 UTC on October 31, setting the stage for a bizarre ending to this storm
By 0600 UT on November 1, central convection had increased to the point where a tropical cyclone (estimated to be of tropical storm intensity) could be identified within the central area of the low . Later it became a true hurricane in every sense of the word. Images of the hurricane phase and a discussion as to why this storm will be remembered in history as the "Unnamed Hurricane" can be found in the Hurricane Gallery of the Satellite's Eye Art Gallery.
Thanks to the National Climatic Data Center for the above history of the storm as well as The Wheelhouse entry page text. You may visit their Web site at www.ncdc.noaa.gov to learn more about the force of nature. |
 "The Barrel of the Gun"Junger provides a description of the formation of a hurricane:
"The mechanics of a hurricane are fundamentally the same as a cutoff low, but their origins differ: hurricanes brew in the lukewarm waters around the equator. When the sun hits the equator it hits it dead-on, a square-foot beam of light heating up exactly one square foot of water. The farther north or south you are, the lower the angle of the sun and the more water a square-foot of sunlight must heat up; as a result the water doesn't heat up as much. The equatorial sea cooks all summer and evaporates huge mounts of water into the air. Evaporated water is unstable and contains energy in the same way that a boulder on top of a hill does-one small push unleashes a huge destructive force. Likewise, a drop in air temperature causes water vapor to precipitate out as rain and release its latent energy back into the atmosphere. The air above one square-foot of equatorial water contains enough latent energy to drive a car two miles. A single thunderstorm could supply four days' worth of the electrical power needed by the United States.
Warm air is less dense than cool air; it rises off the surface of the ocean, cools in the upper atmosphere, and then dumps its moisture before rushing back to earth. Huge cumulus clouds develop over the zones of rising air, with thunder, lightning, and terrifically strong rain. As long as there's a supply of warm water, the thunderstorm sustains itself, converting moisture into sheeting rain and downdraft winds. Other thunderclouds might line up along the leading edge of a cold front into a "squall line," a towering convective engine that stretches from horizon to horizon.
Hurricanes start when a slight kink-- a disturbance in the trade winds, a dust storm blowing out to sea off the Sahara--develops in the upper-level air. The squall line starts to rotate around the kink, drawing in warm, volatile air and sending it up the gathering vortex at its center. The more air that gets drawn in, the faster it spins, and the more water is evaporated off the ocean. The water vapor rises up the core of the system and releases rain and latent heat. Eventually the system starts spinning so fast that inward-spiralling air can no longer overcome the centrifugal force and make it to the center. The eye of the storm has formed, a column of dry air surrounded by a solid wall of wind. Tropical birds get trapped inside and cannot escape. A week later, after the system has fallen apart, frigate birds and egrets might find themselves over Newfoundland or New Jersey.
A mature hurricane is by far the most powerful event on earth; the combined nuclear arsenals of the United States and the former Soviet Union don't contain enough energy to keep a hurricane going for one day. A typical hurricane encompasses a million cubic miles of atmosphere and could provide all the electric power needed by the United States for three or four years." The Perfect Storm pp.127-129 |
