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Tropical Storm Allison

2007 Schools Wikipedia Selection. Related subjects: Storms

   CAPTION: Tropical Storm Allison

   Tropical storm ( SSHS)
   Tropical Storm Allison on June 5, 2001
   Tropical Storm Allison on June 5, 2001
     __________________________________________________________________

   Formed June 4, 2001
   Dissipated June 18, 2001
   Highest
   winds
   60  mph (95  km/h) (1-minute sustained)
   Lowest pressure 1000  mbar ( hPa)
   Damage $5.5 billion (2001 USD)
   $6.05 billion (2006 USD)
   Fatalities 41 direct, 14 indirect
   Areas
   affected Texas (particularly around Houston), Louisiana, most of the
   Eastern United States
   Part of the
   2001 Atlantic hurricane season

   Tropical Storm Allison was a tropical storm that devastated southeast
   Texas in June of the 2001 Atlantic hurricane season. The first storm of
   the season, Allison lasted unusually long for a June storm, remaining
   tropical or subtropical for 15 days. The storm developed from a
   tropical wave in the northern Gulf of Mexico on June 4, and struck the
   northern Texas coast shortly thereafter. It drifted northward through
   the state, then turned back to the south and re-entered the Gulf of
   Mexico. The storm continued to the east-northeast, making landfall on
   Louisiana and then moving across the southeast United States and
   Mid-Atlantic. Allison was the first storm since Tropical Storm Frances
   in 1998 to strike the upper Texas coastline.

   The storm dropped heavy rainfall along its path, peaking at over 40
   inches (1000  mm) in Texas. The worst of the flooding occurred in
   Houston, where most of Allison's damage occurred. There, 30,000 became
   homeless after the flooding destroyed 2,744 homes. Downtown Houston was
   inundated with flooding, causing severe damage to hospitals and
   businesses. 23 people died in Texas. Throughout its entire path,
   Allison caused $6.05 billion (2006 USD) in damage and 41 deaths. Aside
   from Texas, the places worst hit were Louisiana and southeastern
   Pennsylvania.

   Following the storm, President George W. Bush declared 75 counties
   along Allison's path as disaster areas, which allowed the affected
   citizens to apply for aid. Allison is the only tropical storm to have
   its name retired without ever reaching hurricane strength.

Storm history

   Storm path
   Enlarge
   Storm path

   A tropical wave moved off the coast of Africa on May 21. It moved
   westward across the shear-ridden Atlantic Ocean, retaining little
   convection on its way. After moving across South America and the
   southwestern Caribbean Sea, the wave entered the eastern North Pacific
   Ocean on June 1. A low level circulation developed on the 2nd while
   230 miles (370 km) south-southeast of Salina Cruz, Mexico. Southerly
   flow forced the system northward, and the wave moved inland on the 3rd.
   The low-level circulation dissipated, though the mid-level circulation
   persisted. It emerged into the Gulf of Mexico on the 4th, and developed
   deep convection on its eastern side. On June 5, the mid-level
   circulation extended to the surface, and organized into Tropical Storm
   Allison while just 140 miles (225 km) to the south of Galveston, Texas.
   Tropical Storm Allison with an eye-like feature over Mississippi
   Enlarge
   Tropical Storm Allison with an eye-like feature over Mississippi

   Allison initially had subtropical characteristics with an upper level
   low to the southwest of the circulation. Despite this, the storm
   quickly strengthened to a 60 mph (95 km/h) storm, though tropical storm
   force winds extended up to 230 miles (370 km) east of the centre.
   Allison weakened while nearing the Texas coastline, and struck near
   Freeport, Texas as a 50 mph (80 km/h) tropical storm late on June 5.
   The storm quickly weakened over land, and the National Hurricane Centre
   discontinued advisories early on the 6th. The depression drifted
   northward until reaching Lufkin, Texas, where it stalled due to a high
   pressure system to its north. On June 8, the depression drifted to the
   south, then to the southwest. Early on the 10th, Allison again reached
   the Gulf of Mexico just 22 miles (35 km) west of its original landfall
   location. Due to dry air and moderate westerly wind shear, the storm
   transformed into a subtropical cyclone. While the subtropical
   depression moved eastward, a new low level circulation redeveloped to
   the east, and Allison quickly made landfall on Morgan City, Louisiana
   on the 11th. Strong thunderstorms redeveloped over the circulation, and
   Allison strengthened into a subtropical storm over southeastern
   Louisiana.
   Allison over South Carolina
   Enlarge
   Allison over South Carolina

   Allison re-strengthened to reach winds of 45 mph (72 km/h), and an
   eyewall feature briefly existed. The feature was transient, and Allison
   quickly weakened back to a tropical depression. The depression tracked
   to the east-northeast through Mississippi, Alabama, Georgia, and South
   Carolina before becoming nearly stationary near Wilmington, North
   Carolina. It drifted through the state, and accelerated to the
   northeast in response to an approaching cold front. Allison reached the
   Atlantic Ocean on June 17, and briefly reintensified to a subtropical
   storm through baroclinic processes. Allison became extratropical while
   south of Long Island on the 18th, and was absorbed by the cold front on
   the 19th.

Preparations

   Shortly after forming, officials in Galveston County, Texas issued a
   voluntary evacuation for the western end of Galveston Island. This was
   due to fears of coastal flooding, as the area was not protected by the
   Galveston Seawall. The ferry from the island to the Bolivar Peninsula
   was closed, while voluntary evacuations were issued in Surfside in
   Brazoria County. Voluntary evacuations were also suggested near Sabine
   Pass in Jefferson County, Texas, though few left. Also, when the
   National Hurricane Centre issued the first advisory on Allison,
   officials issued Tropical Storm Warnings from Sargent, Texas to Morgan
   City, Louisiana, just 3 hours before tropical storm winds were
   observed.

   After the storm made landfall, flash flood watches and warnings were
   issued for numerous areas in eastern Texas. In addition, traveling was
   discouraged due to the threat for flash flooding. During the flood
   event, the National Weather Service in Houston issued 99 flash flood
   warnings with an average lead time of 40 minutes. In addition, there
   were only nine warnings that were false alarms. With an average lead
   time of 24 minutes, the National Weather Service in Lake Charles,
   Louisiana issued 47 flash flood warnings, of which eleven were false
   alarms. One flash flood occurred outside of the warning area. With an
   average lead time of 39 minutes, the National Weather Service in New
   Orleans/Baton Rouge issued 87 flash flood warnings, of which 30 were
   not followed by a flash flood. In addition, there were five flash
   floods not covered in the warning area.

   In Tallahassee, Florida, a shelter was opened the day prior to Allison
   moving north through the area, with seven staff members housing
   12 people. Two other shelters were put on standby. Teams informed
   citizens in the Florida Panhandle of flood dangers.

Impact

                                             CAPTION: Death Tolls by State

                                                               Area Deaths
                                                              Texas     23
                                                          Louisiana      1
                                                        Mississippi      1
                                                            Florida      8
                                                           Virginia      1
                                                       Pennsylvania      7
                                                              Total     41

   Tropical Storm Allison was a major flooding disaster throughout its
   path from Texas to the Mid-Atlantic. The worst of the flooding occurred
   in Houston, Texas, where over 35 inches (890 mm) of rain fell. Allison
   killed 41 people, of which 27 drowned from the flooding. The storm also
   caused over $5 billion in damage (2001 USD, $6.05 billion 2006 USD),
   making Allison the deadliest and costliest tropical storm on record in
   the United States.

Texas

   Allison made landfall with a storm surge of two to three feet. Combined
   with waves on top, areas of Galveston Island experienced a wall of
   water 8 feet (2.5 m) in height, creating overwash along the coastline.
   The storm caused winds of up to 43 mph (69 km/h) at the Galveston Pier.
   While Allison was stalling over Texas, it dropped heavy rainfall across
   the state, including 9.77 inches (248 mm) in Galveston, 12.13 inches
   (308 mm) in Jamaica Beach, Texas, and other similar totals along the
   coast. Minimal beach erosion was reported. Impact was minimal near the
   coast.

   While moving northward through Texas as a minimal tropical depression,
   Allison produced minor wind gusts. Shortly after making landfall, the
   storm spawned a tornado in Manvel of Brazoria County, causing damage to
   one home. Within hours of making landfall, rainfall totals of 8 to 12
   inches (200 to 300 mm) were common in Galveston and Harris County.
   Flash flooding continued for days, with rainfall amounts across the
   state peaking at just over 40 inches (1033 mm) in northwestern
   Jefferson County. In the Port of Houston, a total of 36.99 inches
   (940 mm) was reported.
   Flooding from Allison
   Enlarge
   Flooding from Allison

   Houston experienced torrential rainfall in a short amount of time.
   6.3 inches (160 mm) fell in just one hour, while 28.5 inches (724 mm)
   fell in only 12 hours. The six-day rainfall in Houston amounted to
   38.6 inches (980 mm). Two-thirds of the bayous and creeks in Harris
   County experienced 500-year flood events. Houston, which typically
   receives 46.07 inches (1170 mm) of rain in a year, experienced 35.7% of
   its expected total in the first nine days of June.

   The deluge of rainfall flooded 95,000 automobiles and 73,000 houses
   throughout Harris County. Tropical Storm Allison destroyed 2,744 homes,
   leaving 30,000 homeless with residential damages totaling to
   $1.76 billion (2001 USD, $1.94 billion 2006 USD). Residential
   neighborhoods inside and to the north of Interstate 610 were hardest
   hit.

   Several hospitals in the Texas Medical Centre experienced severe damage
   from the storm. When the serious flooding began on June 9, hospitals
   evacuated more than 1,000 patients. The flooding occurred through
   below-grade pedestrian tunnels that link many major buildings. Most
   lost power and backup power when basements, the area where power and
   research data were kept, flooded. The Baylor College of Medicine
   experienced the worst of the damage, totaling to $495 million (2001
   USD, $547 million 2006 USD). There, the hospital lost 90,000 research
   animals, 60,000 tumor samples, and 25 years of research data.
   Throughout the Medical centre, damage totaled to over $2 billion (2001
   USD, $2.2 billion 2006 USD). Most were reopened after a month, though
   it took much longer to become fully operational.

   The underground tunnel system, which connects most large office
   buildings in Downtown Houston, was submerged, as were many streets and
   parking garages adjacent to the Buffalo Bayou. At the Theatre District,
   also in downtown, the Houston Symphony, Houston Grand Opera, and Alley
   Theatre lost millions of dollars of costumes, musical instruments,
   sheet music, archives and other artifacts. Local television stations
   ran all-night coverage of the deluge from June 8 through the next day,
   including KHOU-TV 11, which was forced to transmit its broadcast to a
   satellite truck when floodwaters entered its production studio. By
   midnight June 9 nearly every freeway and major road in the city was
   underwater, forcing hundreds of motorists to abandon their vehicles for
   higher ground.

   Despite massive flooding damage to entire neighborhoods there were no
   drowning deaths in flooded homes. In the area, there were 12 deaths
   from driving, 6 from walking, 3 from electrocution, and 1 in an
   elevator. Elsewhere in Texas, a man drowned when swimming in a ditch in
   Mauriceville. Damage totaled to $5.2 billion (2001 USD, $5.7 billion
   2006 USD) throughout Texas.

   Though Allison's flooding was extreme, it was not unprecedented.
   Tropical Storm Amelia in 1978 dropped over 46 inches (1170 mm) of
   rainfall in Bluff, Texas, which remains the record highest rainfall for
   a single storm in the state of Texas. In addition, Tropical Storm
   Claudette in 1979 and a hurricane in 1921 produced rainfall totals of
   over 40 inches (1015 mm).

Louisiana

   Flooding in Chackbay, Louisiana
   Enlarge
   Flooding in Chackbay, Louisiana

   While making its first landfall, Allison's large circulation dropped
   severe rains on southwest Louisiana. Days later, Allison hit the state
   as a subtropical storm, dropping more heavy rains to the area. Rainfall
   totals peaked at 29.86 inches (758 mm) in Thibodaux, the highest
   rainfall total in Louisiana from a tropical cyclone since a previous
   Tropical Storm Allison in 1989. Most of the southeastern portion of the
   state experienced over 10 inches of rain (255 mm). Winds were generally
   light, peaking at 38 mph (61 km/h) sustained in Lakefront with gusts to
   53 mph (85 km/h) in Bay Gardene. The storm produced a storm surge of
   2.5 feet (0.75 m) in Cameron as it was making landfall in Texas. While
   moving northward through Texas, the outer bands of the storm produced
   an F1 tornado near Zachary, damaging several trees and a power line. A
   man was killed when a damaged power line hit his truck.

   When Allison first made landfall, heavy rainfall flooded numerous
   houses and businesses. Minor wind gusts caused minor roof damage to
   10 houses in Cameron Parish, while its storm surge flooded portions of
   Louisiana Highway 82. When the system returned, more rainfall occurred,
   flooding over 1,000 houses in St. Tammany Parish, 80 houses in Saint
   Bernard Parish, and hundreds of houses elsewhere in the state. The
   flooding also forced 1,800 residents from their homes in East Baton
   Rouge Parish. The deluge left numerous roads impassable, while runoff
   resulted in severe river flooding. The Bogue Falaya River in Covington
   crested past its peak twice to near record levels. The Amite and Comite
   Rivers reached their highest levels since 1983. In addition, the levee
   along the Bayou Manchac broke, flooding roadways and more houses.
   Damage in Louisiana totaled to $65 million (2001 USD, $72 million 2006
   USD).

Southeast United States

   Rainfall totals from Allison
   Enlarge
   Rainfall totals from Allison

   In Mississippi, Allison produced heavy rainfall of over 10 inches
   (255 mm) in one night, while some areas in the southwestern portion of
   the state received over 15 inches (380 mm). The flooding damaged
   numerous houses and flooded many roadways. Thunderstorms from the storm
   produced four tornadoes, including one in Gulfport, Mississippi that
   damaged 10 houses. Severe thunderstorms in George County damaged 15
   houses, destroyed 10, and injured five people. Damage in Mississippi
   totaled to over $1 million (2001 USD, $1.1 million 2006 USD). Rainfall
   in Alabama was moderate, with areas near Mobile experiencing more than
   10 inches (255 mm). Heavy rainfall closed several roads in Crenshaw
   County. The storm, combined with a high pressure, produced coastal
   flooding in southern Alabama. Allison produced an F0 tornado in
   southwest Mobile County that caused minor roof damage and another F0
   tornado in Covington County that caused minor damage to six homes and a
   church.

   The storm, combined with a high pressure system, produced a strong
   pressure gradient, resulting in strong rip currents off the coast of
   Florida. The currents prompted sirens, which are normally used for
   storm warnings, to be activated in Pensacola Beach. The rip currents
   killed 5 off the coast of Florida. Outer rain bands from the storm
   dropped heavy rainfall across the Florida Panhandle of over 11 inches
   (280 mm) in one day. The Tallahassee Regional Airport recorded
   10.13 inches (257 mm) in 24 hours, breaking the old 24 hour record set
   in 1969. Throughout the state, Allison destroyed 10 homes and damaged
   599, 196 severely, primarily in Leon County. Including the deaths from
   rip currents, Allison killed eight people in Florida and caused
   $20 million (2001 USD, $22 million 2006 USD) in damage.

   Over Georgia, the storm dropped heavy rainfall of 10 inches (255 mm) in
   24 hours in locations. The deluge caused rivers to crest past their
   banks, including the Oconee River at Milledgeville which peaked at
   33.7 feet (10.3 m). The rainfall, which was heaviest across the
   southwestern portion of the state, washed out several bridges and
   roads, and flooded many other roads. Georgia governor Roy Barnes
   declared a state of emergency for seven counties in the state. The
   storm also spawned two tornadoes. In South Carolina, Allison's outer
   bands produced 10 tornadoes and several funnel clouds, though most only
   caused minor damage limited to a damaged courthouse, snapped trees and
   downed power lines. Allison produced from 12 to 16 inches (305 to
   406 mm) of rainfall in North Carolina, closing nearly all roads in
   Martin County and damaging 25 homes. The severe flooding washed out a
   bridge in eastern Halifax County and flooded numerous cars. Wet roads
   caused nine traffic accidents throughout the state.

Mid-Atlantic and Northeast United States

   Damage from flooding in Pennsylvania
   Enlarge
   Damage from flooding in Pennsylvania

   In Virginia, Allison produced light rainfall, with the southeastern and
   south-central portions of the state experiencing over 3 inches (76 mm).
   A tree in a saturated ground fell over and killed one person. Allison
   also produced one tornado in the state. Washington, D.C. experienced
   moderate rainfall from the storm, totaling to 2.59 inches (66 mm) in
   Georgetown. In Maryland, rainfall from Tropical Depression Allison
   totaled to 7.5 inches (190 mm) in Denton, closing eleven roads and
   causing washouts on 41 others. The Maryland Eastern Shore experienced
   only minor rainfall from one to two inches (25 to 50 mm). Damage was
   light, and no deaths were reported. In Delaware, the storm produced
   moderate rainfall, peaking at 4.2 inches (106 mm) in Greenwood. No
   damage was reported.

   Allison, in combination with an approaching frontal boundary, dropped
   heavy rainfall across southeastern Pennsylvania, peaking at
   10.17 inches (258 mm) in Chalfont in Bucks County and over 3 inches
   (76 mm) in portions of Philadelphia. The rainfall caused rivers to
   rise, with the Neshaminy Creek in Langhorne peaking at 16.87 feet
   (5 m). Several other rivers and creeks in southeastern Pennsylvania
   crested at over 10 feet (3 m). The rainfall downed numerous weak trees
   and power lines, leaving 70,000 without power during the storm. The
   flooding washed out several roads and bridges, including a few SEPTA
   rail lines. In addition, the rainfall destroyed 241 homes and damaged
   1,386 others. Flooding at a Dodge dealership totaled 150 vehicles.
   Hundreds of people were forced to be rescued from damaged buildings
   from flood waters. The flooding dislodged a clothes dryer in the
   basement of the "A" building of the Village Green Apartment Complex in
   Upper Moreland Township, breaking a natural gas line. The gas leak
   resulted in an explosion and an ensuing fire that killed six people.
   Firefighters were unable to render assistance as the building was
   completely surrounded by floodwaters. Additionally, one man drowned in
   his vehicle in a river. Damage in Pennsylvania totaled to $215 million
   (2001 USD, $237 million 2006 USD).

   In New Jersey, the storm produced heavy rainfall, peaking at 8.1 inches
   (205 mm) in Tuckerton. The rains also caused river flooding, including
   the north branch of the Metedeconk River in Lakewood which crested at
   8 feet (2.5 m). The flooding, severe at places, closed several roads,
   including numerous state highways. Gusty winds of up to 44 mph
   (71 km/h) in Atlantic City downed weak trees and power lines, leaving
   over 13,000 without power. Several people had to be rescued from high
   waters, though no fatalities occurred in the state. Overall damage was
   minimal.

   Tropical Storm Allison caused flash flooding in New York, dropping up
   to 3 inches (75 mm) of rain in one hour in several locations and
   peaking at 5.73 inches (146 mm) in Granite Springs. The rains also
   caused river flooding, including the Mahwah River which crested at
   3.79 feet (1 m). Allison's rainfall damaged 24 houses and several
   stores, while the flooding closed several major highways in the New
   York City area. Overall damage was light, and no fatalities occurred in
   New York due to Allison. Similarly, rainfall in Connecticut peaked at
   7.2 inches (183 mm) in Pomfret, closing several roads and causing minor
   damage to numerous houses. The Yantic River at Yantic crested at
   11.1 feet (3.4 m), while a state road was closed when a private dam in
   Hampton failed from the rainfall. In Rhode Island, Allison produced up
   to 7.1 inches (180 mm) of rainfall in North Smithfield, washing out
   several roads and houses, and destroying a log house in Foster.

   An isolated severe thunderstorm in the outer bands of Allison produced
   an F1 tornado in Worcester and Middlesex Counties in Massachusetts,
   impacting over 100 trees and damaging one house and one small camper. A
   microburst in Leominster and another in Shirley damaged several trees.
   Lightning from the storm hit two houses, causing significant damage
   there but little elsewhere. Allison also produced moderate rainfall in
   the state, mainly ranging from 3 to 5 inches (75 to 125 mm). The
   rainfall caused drainage and traffic problems. Damage in Massachusetts
   totaled to $400,000 (2001 USD, $440,000 2006 USD).

Aftermath

   Within weeks of the disaster, President George W. Bush declared
   28 counties in Texas, southern Louisiana, southern Mississippi,
   northwestern Florida, and southeastern Pennsylvania as disaster areas.
   The declarations allowed affected citizens to receive aid for temporary
   housing, emergency home repairs, and other serious disaster-related
   expenses. FEMA also provided 75% for the cost of debris removal,
   emergency services related to the disaster, and repairing or replacing
   damaged public facilities, such as roads, bridges and utilities.
   Aid from the American Red Cross
   Enlarge
   Aid from the American Red Cross

   A few weeks after Allison, FEMA opened 6 disaster recovery centers
   across southeast Texas, which provided recovery information to those
   who applied for disaster assistance. The American Red Cross and the
   Salvation Army opened 48 shelters at the peak of need for people driven
   from their homes, which served nearly 300,000 meals. After the
   extensive damage to Houston hospitals, the U. S. Public Health Service
   team set up a temporary hospital at the Houston Police Academy. The
   team of 87 medical personnel served over 1,000 patients within two
   weeks of Allison's passage. Similarly, the National Disaster Medical
   System deployed a temporary hospital to Houston with 88 professionals,
   aiding nearly 500 people. Debris removal, which was initially slow, was
   aided by FEMA to expedite the removal process. FEMA provided 75% of the
   federal cost of the removal. 35 volunteer services provided aid for the
   flood victims in Texas, including food, clothing, and volunteers to
   help repair the houses.
   Texas Department of Transportation official warns of damaged cars
   Enlarge
   Texas Department of Transportation official warns of damaged cars

   After nearly 50,000 cars were flooded and ruined, many people attempted
   to sell the cars across the country without telling of the car's
   history. Following the extreme flooding, a mosquito outbreak occurred,
   though FEMA provided aid to control the problem. Health officials also
   recommended disinfecting private wells with bleach, due to possible
   contamination from the severe flooding. Many people took advantage of
   the flood victims, including fraudulent contractors and suppliers
   raising the price of goods more than is actually justified.

   By six months after the storm, around 120,000 Texas citizens applied
   for federal disaster aid, totaling to $1.05 billion (2001 USD,
   $1.16 billion 2006 USD). 17% of that was spent for temporary housing.
   In addition, Disaster Unemployment Assistance totaled to just under $1
   million, while business loans totaled to $389 million (2001 USD,
   $428 million 2006 USD).

   Like in Texas, a mosquito outbreak occurred in Louisiana. Only
   pesticides acceptable to the US Environmental Protection Agency and the
   US Fish and Wildlife Service were allowed to be used. FEMA officials
   warned homeowners of the dangers of floodwaters, including mold,
   mildew, and bacteria. By three months after the storm, just under
   100,000 Louisiana citizens applied for federal aid, totaling to over
   $110 million (2001 USD, $118 million 2005 USD). $25 million (2001 USD,
   $28 million 2006 USD) of the total was for business loans, while an
   additional $8 million was for public assistance for communities and
   state agencies. More than 750 flood victims in Florida applied for
   governmental aid, totaling to $1.29 million (2001 USD, $1.4 million
   2006 USD). In Pennsylvania, 1,670 flood victims applied for federal
   aid, totaling to $11.5 million (2001 USD, $12.7 million 2005 USD).
   $3.4 million (2001 USD, $3.7 million 2005 USD) of the total was to
   replace a SEPTA rail bridge over the Sandy Run Creek in Fort
   Washington.

Retirement

   The name Allison was retired in the spring of 2002 and will never again
   be used in the Atlantic basin; the 2001 incarnation of Allison is the
   only Atlantic tropical system ever to have its name retired without
   ever reaching hurricane strength. The name will be replaced with Andrea
   in the 2007 season.

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