Hurricane Isabel

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Hurricane Isabel
Category 5 major hurricane (SSHWS/NWS)
Hurricane Isabel 11 sept 2003 1415Z (Cropped).jpg
Hurricane Isabel near peak intensity northeast of the Leeward Islands, on September 11
FormedSeptember 6, 2003
DissipatedSeptember 20, 2003
(Extratropical after September 19)
Highest winds1-minute sustained: 165 mph (270 km/h)
Lowest pressure915 mbar (hPa); 27.02 inHg
Fatalities17 direct, 34 indirect
Damage$5.5 billion (2003 USD)
Areas affectedLesser Antilles, Puerto Rico, Greater Antilles, Turks and Caicos Islands, Bahamas, East coast of the United States, Atlantic Canada
Part of the 2003 Atlantic hurricane season
Part of a series on Hurricane Isabel

Hurricane Isabel was the costliest, deadliest, and strongest hurricane in the 2003 Atlantic hurricane season. The ninth named storm, fifth hurricane, and second major hurricane of the season, Isabel formed near the Cape Verde Islands from a tropical wave on September 6, in the tropical Atlantic Ocean. It moved northwestward, and within an environment of light wind shear and warm waters, it steadily strengthened to reach peak winds of 165 mph (265 km/h) on September 11. After fluctuating in intensity for four days, during which Isabel displayed annular characteristics, Isabel gradually weakened and made landfall on the Outer Banks of North Carolina, with winds of 105 mph (165 km/h) on September 18. Isabel quickly weakened over land and became extratropical over western Pennsylvania on the next day. On September 20, the extratropical remnants of Isabel were absorbed into another system over Eastern Canada.

In North Carolina, the storm surge from Isabel washed out a portion of Hatteras Island to form what was unofficially known as Isabel Inlet. Damage was greatest along the Outer Banks, where thousands of homes were damaged or even destroyed. The worst of the effects of Isabel occurred in Virginia, especially in the Hampton Roads area and along the shores of rivers as far west and north as Richmond and Washington, DC. Virginia reported the most deaths and damage from the hurricane. About 64% of the damage and 69% of the deaths occurred in North Carolina and Virginia. Electric service was disrupted in areas of Virginia for several days, some more rural areas were without electricity for weeks, and local flooding caused thousands of dollars in damage.

Moderate to severe damage extended up the Atlantic coastline and as far inland as West Virginia. Roughly six million people were left without electric service in the eastern United States from the strong winds of Isabel. Rainfall from the storm extended from South Carolina to Maine, and westward to Michigan. Throughout the path of Isabel, damage totalled about $5.5 billion (2003 USD). 16 deaths in seven U.S. states were directly related to the hurricane, with 35 deaths in six states and one Canadian province indirectly related to the hurricane.

Meteorological history[edit]

Map plotting the track and intensity of the storm, according to the Saffir–Simpson scale

A tropical wave moved off the western coast of Africa on September 1.[1] An area of low pressure associated with the wave moved slowly westward, and its convection initially appeared to become better organized.[2] On September 3, as it passed to the south of the Cape Verde islands, organization within the system degraded,[3] though convection increased the next day.[4] The system gradually became better organized, and Dvorak classifications began early on September 5. Based on the development of a closed surface circulation, it is estimated the system developed into Tropical Depression Thirteen early on September 6. Hours later, it intensified into Tropical Storm Isabel,[1] though operationally the National Hurricane Center did not begin issuing advisories until 13 hours after it first developed.[5]

Located within an area of light wind shear and warm waters, Isabel gradually organized as curved bands developed around a circular area of deep convection near the center.[6] It steadily strengthened as it moved to the west-northwest, and Isabel strengthened to a hurricane on September 7 subsequent to the development of a large, yet ragged eye located near the deepest convection.[7] The eye, overall convective pattern, and outflow steadily improved in organization,[8] and deep convection quickly surrounded the 40-mile (60 km)-wide eye.[9] Isabel intensified on September 8 to reach major hurricane status while located 1,300 miles (2,100 km) east-northeast of Barbuda. On September 9, Isabel reached an initial peak intensity of 135 mph (215 km/h) for around 24 hours, a minimal Category 4 hurricane on the Saffir–Simpson Hurricane Scale.[1]

The eye of Hurricane Isabel as seen from the International Space Station
Hurricane Isabel displaying annular characteristics on September 14, as a powerful Category 5 hurricane
Broader view from the International Space Station

Early on September 10, the eyewall became less defined, the convection near the eye became eroded, and northeasterly outflow became slightly restricted.[10] As a result, Isabel weakened slightly to a Category 3 hurricane. The hurricane turned more to the west due to the influence of the Bermuda-Azores High.[1] Later on September 10, Isabel restrengthened to a Category 4 hurricane after convection deepened near the increasingly organizing eyewall.[11] The hurricane continued to intensify, and Isabel reached its peak intensity of 165 mph (270 km/h) on September 11, a Category 5 hurricane on the Saffir–Simpson Hurricane Scale.[1] Due to an eyewall replacement cycle, Isabel weakened slightly, though it retained Category 5 status for 24 hours.[12] As Isabel underwent another eyewall replacement cycle, outflow degraded in appearance and convection around the eye weakened,[13] and early on September 13, Isabel weakened to a strong Category 4 hurricane. A weakness in the ridge to its north allowed the hurricane to turn to the west-northwest.[1] After completing the replacement cycle, the hurricane's large 40 mile (65 km) wide eye became better defined,[14] and late on September 13, Isabel re-attained Category 5 status.[1] During this time, Isabel attained annular characteristics, becoming highly symmetrical in shape and sporting a wide eye.[1] A NOAA Hurricane Hunter Reconnaissance Aircraft flying into the hurricane launched a dropsonde which measured an instantaneous wind speed of 233 mph (375 km/h), the strongest instantaneous wind speed recorded in an Atlantic hurricane.[15] Cloud tops warmed again shortly thereafter,[16] and Isabel weakened to a strong Category 4 hurricane early on September 14. Later that day, it re-organized, and for the third time, Isabel attained Category 5 status while located 400 miles (650 km) north of San Juan, Puerto Rico.[1]

Cloud tops around the center warmed again early on September 15, and Isabel weakened to a Category 4 hurricane.[1] Later that day, the inner core of deep convection began to deteriorate, while the eye decayed in appearance. As a ridge to its northwest build southeastward, it resulted in Isabel decelerating as it turned to the north-northwest.[17] Increasing vertical wind shear contributed in weakening the hurricane further, and Isabel weakened to a Category 2 hurricane on September 16, while located 645 miles (1035 km) southeast of Cape Hatteras, North Carolina.[1] Convection remained minimal, though outflow retained excellent organization,[18] and Isabel remained a Category 2 hurricane for two days, until it made landfall between Cape Lookout and Ocracoke Island on September 18, with winds of 105 mph (165 km/h). The system weakened after it made landfall, though due to its fast forward motion, Isabel remained a hurricane until it reached western Virginia, early on September 19. After passing through West Virginia as a tropical storm, Isabel became extratropical over Western Pennsylvania, near Pittsburgh. The system continued turned northward, and crossed Lake Erie into Canada. Early on September 20, the extratropial remnant of Isabel was absorbed by a larger extratropical storm, over the Cochrane District of Ontario.[1]

Preparations[edit]

Hurricane Isabel making landfall in North Carolina on September 18

Two days before Isabel made landfall, the National Hurricane Center issued a hurricane watch from Little River, South Carolina to Chincoteague, Virginia, including the Pamlico and Albemarle Sounds and the lower Chesapeake Bay. The NHC also issued a tropical storm watch south of Little River, South Carolina to the mouth of the Santee River, as well as from Chincoteague, Virginia northward to Little Egg Inlet, New Jersey. Hurricane and tropical storm warnings were gradually issued for portions of the East Coast of the United States. By the time Isabel made landfall, a tropical storm warning existed from Chincoteague, Virginia to Fire Island, New York and from Cape Fear, North Carolina to the mouth of the Santee River in South Carolina, and a hurricane warning existed from Chincoteague, Virginia to Cape Fear. Landfall forecasts were very accurate; from three days prior, the average track forecast error for its landfall was only 36 miles (58 km), and for 48 hours in advance the average track error was 18 miles (29 km).[1]

Officials declared mandatory evacuations for 24 counties in North Carolina, Virginia, and Maryland, though in general not many left. According to a survey conducted by the United States Department of Commerce, evacuation rates were estimated as follows; 45% in the Outer Banks, 23% in the area around the Pamlico Sound, 23% in Virginia, and about 15% in Maryland.[19] The threat of Isabel resulted in the evacuation of hundreds of thousands of residents, primarily in North Carolina and Virginia, and included more than 12,000 residents staying in emergency shelters.[20]

19 major airports along the East Coast of the United States were closed, with more than 1,500 flights canceled. The Washington Metro and Metrobus system closed prior to the arrival of the storm, and Amtrak canceled nearly all trains south of the nation's capital. Schools and businesses throughout its path closed prior to Isabel's arrival to allow time to prepare; hardware and home improvement stores reported brisk business of plywood, flashlights, batteries, and portable generators, as residents prepared for the storm's potential impact. The federal government was closed excluding emergency staff members.[20] The United States Navy ordered the removal of 40 ships and submarines and dozens of aircraft from naval sites near Norfolk, Virginia.[21]

A contingency plan was established at the Tomb of the Unknowns at Arlington National Cemetery that, should the winds exceed 120MPH, the guards could take positions in the trophy room (above the Tomb Plaza and providing continual sight of the Tomb) but the plan was never implemented. However, it spawned an urban legend that the Third Infantry sent orders to seek shelter, orders that were deliberately disobeyed.[22]

On September 18, the Canadian Hurricane Centre issued heavy rainfall and wind warnings for portions of southern Ontario. A gale warning was also issued for Lake Ontario, eastern Lake Erie, the Saint Lawrence River and Georgian Bay.[23][24][25] A news report on September 14 warned conditions could be similar to the disaster caused by Hurricane Hazel 49 years prior, resulting in widespread media coverage on the hurricane.[26] Researchers on a Convair 580 flight studied the structure of Isabel transitioning into an extratropical storm, after two similar studies for Hurricane Michael in 2000 and Tropical Storm Karen in 2001. While flying in a thunderstorm, ice accumulation forced the plane to descend.[27]

Impact[edit]

Deaths and damage by region
RegionDeathsDamage
(2003 USD)
DirectIndirect
Florida100
North Carolina12$450 million
Virginia1022>$1.85 billion
West Virginia00$20 million
Washington, D.C.01$125 million
Maryland16$820 million
Delaware00$40 million
Pennsylvania02$160 million
New Jersey11$50 million
New York10$90 million
Rhode Island100
Ontario01?
Total1635$5.5 billion

Strong winds from Isabel extended from North Carolina to New England and westward to West Virginia. The winds, combined with previous rainfall which moistened the soil, downed many trees and power lines across its path, leaving about 6 million electricity customers without power at some point. Parts of coastal Virginia, especially in the Hampton Roads and Northeast North Carolina areas, were without electricity for almost a month. Coastal areas suffered from waves and its powerful storm surge, with areas in eastern North Carolina and southeast Virginia reporting severe damage from both winds and the storm surge. Throughout its path, Isabel resulted in $5.5 billion in damage (2003 USD) and 51 deaths, of which 16 were directly related to the storm's effects.[28][29]

The governors of Pennsylvania, West Virginia, Maryland, New Jersey, and Delaware declared states of emergency.[20] Isabel was the first major hurricane to threaten the Mid-Atlantic States and the Upper South since Hurricane Floyd in September 1999. Isabel's greatest effect was due to flood damage, the worst in some areas of Virginia since 1972's Hurricane Agnes. More than 60 million people were affected to some degree—a similar number to Floyd but more than any other hurricane in recent memory.[30]

Caribbean and Southeast United States[edit]

Rainfall totals from Hurricane Isabel

Powerful surf affected the northern coastlines of the islands in the Greater Antilles. Strong swells also lashed the Bahamas. During most hurricanes, the location of the Bahamas prevents powerful swells of Atlantic hurricanes from striking southeast Florida. However, the combination of the location, forward speed, and strength of Isabel produced strong swells through the Providence Channel onto a narrow 10 mile (16 km) stretch of the southeastern Florida coastline; wave heights peaked at 14 feet (4.3 m) at Delray Beach.[15] The swells capsized a watercraft and injured its two passengers at Boynton Beach, and a swimmer required assistance to be rescued near Juno Beach. Minor beach erosion was reported in Palm Beach County.[31] In the northern portion of the state, waves reached up to 15 feet (4.5 m) in height at Flagler Beach, causing the Flagler Beach Pier to be closed due to damaged boards from the waves.[32] Rip currents from Isabel killed a surfer at an unguarded beach in Nassau County, with an additional six people requiring rescue from the currents.[33] The beaches were later closed during the worst of the rough surf.[34]

In northeastern South Carolina, the outer rainbands produced moderate winds reaching 45 mph (72 km/h) at Myrtle Beach. Rainfall was light, peaking at 1.34 inches (34 mm) in Loris.[35]

North Carolina[edit]

Isabel produced moderate to heavy damage across eastern North Carolina, totaling $450 million (2003 USD).[1] Damage was heaviest in Dare County, where storm surge flooding and strong winds damaged thousands of houses.[36] The storm surge produced a 2,000 foot (600 m) wide inlet on Hatteras Island, unofficially known as Isabel Inlet, isolating Hatteras by road for two months.[37] Strong winds downed hundreds of trees of across the state, leaving up to 700,000 residents without power. Most areas with power outages had power restored within a few days.[36] The hurricane directly killed one person and indirectly killed two in the state.[38]

Virginia[edit]

Flood waters at Langley AFB, Hampton, Virginia as a result of Hurricane Isabel

The storm surge assailed much of southeastern Virginia causing the worst flooding seen in the area since the 1933 Chesapeake–Potomac hurricane, peaking at an estimated 9 feet (2.7 m) in Richmond along the James River. The surge caused significant damage to homes along r