Review of the past hurricane season



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WORLD METEOROLOGICAL ORGANIZATION

___________________________________________

RA IV HURRICANE COMMITTEE


THIRTY-FIFTH SESSION
WILLEMSTAD, CURAçAO
8 TO 12 APRIL 2013




RA IV/HC-35/Doc. 4.2(4)

(11.III.2013)

________

ITEM 4.2


Original: ENGLISH


REVIEW OF THE PAST HURRICANE SEASON
Reports of hurricanes, tropical storms, tropical disturbances and

related flooding during 2012
Report from United States of America
(Submitted by USA)

The 2012 Atlantic hurricane season was marked by above average tropical cyclone activity, and the United States was affected by several tropical storms and hurricanes. The cyclones caused near $53billion in damage and 83 deaths. Figure 1 shows the track of the cyclones that affected the United States.


Tropical Storm Beryl
Beryl made landfall around 0410 UTC May 28 near Jacksonville Beach, Florida as a 65-mph tropical storm. After landfall, Beryl weakened to a tropical depression as it moved west-northwestward across northeastern Florida at a slower forward speed. Beryl began to recurve northeastward later that day, and this motion brought the center across southeastern Georgia and into southern South Carolina early on May 30.
Beryl brought tropical storm conditions to portions of northeastern Florida and southeastern Georgia on May 27-28, and to portions of South Carolina and southern North Carolina on May 30. As a post-tropical cyclone, Beryl produced gale-force winds along portions of the North Carolina Outer Banks.
Beryl produced storm surge values of 1-3 feet above normal tide levels along portions of the northeastern Florida and southeastern Georgia coasts, with the highest reported surge being 3.73 feet above normal tide levels at Fernandina Beach, Florida. These surges resulted in maximum inundations of 2-3 feet above ground level. Storm surges of 1-3 feet also occurred along portions of the coasts of South and North Carolina.

Beryl generated a large area of rainfall in excess of 10 inches across northern Florida, with Wellborn reporting a storm total of 15.00 inches. The rain caused minor inland flooding. Additional rainfall of 3-7 inches, with isolated heavier amounts, occurred from northeastern Florida across southeastern Georgia and southern South Carolina into eastern North Carolina



Beryl spawned four tornadoes. The strongest tornadoes were an EF-1 tornado near Truttney’s Landing, North Carolina on May 30, which destroyed three mobile homes and damaged over 60 other homes, and another EF-1 tornado that occurred near Holly Hill, South Carolina on May 29.
Beryl directly caused one death when a severe thunderstorm associated with the cyclone blew down a tree onto an SUV in Orangeburg County, South Carolina, killing the occupant. The storm caused only minor property damage in the United States.
Tropical Storm Debby
Debby made landfall with 40 mph winds near Steinhatchee, Florida around 2100 UTC June 26. The cyclone crossed north-central Florida that evening and weakened to a tropical depression near Gainesville around 0000 UTC June 27. Debby moved across the remainder of northern Florida and emerged offshore of the northeastern Florida coast by 1200 UTC 27 as an extratropical low.
There were five direct deaths attributed to Debby. A tornado threw a mother and her 3-year-old child from their mobile home in Venus, Florida, killing the mother. Two people drowned in rough surf conditions – one in Pinellas County, Florida, and the other in Orange Beach, Alabama. Another person drowned after his canoe capsized near Lake Dorr, Florida, in Lake County. A man was found floating in flood waters near Anclote Key, Florida, and was presumed to have been drowned by the storm.
Freshwater flooding from heavy rains (Figure 2) across portions of northern and central Florida caused damage to at least 400 structures near the Sopchoppy River. Flooding also occurred along the Anclote and Pithlachascotee Rivers in Pasco County, which resulted in “head deep” water in several nearby communities. The river flooding, combined with inundating rains related to the storm, caused damage to 106 homes in the county. In Live Oak, flood levels along the Suwanee River were the highest observed since Hurricane Dora in 1964. Floodwaters caused portions of U.S. Highway 90 to be closed for nearly two weeks. Flooding on the St. Mary’s River spilled over onto Interstate 10, and closed the highway for two days. Finally, in Clay County, the overflow of Black Creek resulted in the inundation of 587 nearby residences. Roads in several communities were either impassable or washed away, and there were reports of bridge collapses at a number of locations.
Storm surge flooding affected coastal areas of the Florida Panhandle and Florida Big Bend. Numerous roads and some area businesses in Saint Marks and Panacea were under water, while the surge reportedly submerged portions of U.S. Highway 98. High water was reported across many roads, with Alligator Point Road and Indian Pass Road significantly damaged or washed out in a few places. Along the west-central Florida coast, similar storm surge flooding was reported along U.S. Highway 19 near Hudson and also on the Suncoast Parkway, which was closed for a week due to standing water. Beach erosion was especially severe across this region due to several days of continuous onshore flow, especially from Charlotte County northward through Pinellas County. The worst beach erosion occurred in Treasure and Anna Maria Islands.
Nine oil production platforms and one oil drilling rig were damaged. Overall U.S. oil production decreased by as much as 2% on June 25 as oil production was temporarily suspended due to the storm.
Total damage losses are estimated to be $250 million. However, this total does not include flood damage estimates from FEMA’s National Flood Insurance Program (NFIP). Once this estimate is available, the total damage for Debby will likely be much higher.
Hurricane Isaac
Isaac moved west-northwestward on August 26, paralleling the northern coast of Cuba and passed south of the Florida Keys later in the day. Tropical-storm-force winds, especially in gusts, affected the Florida Keys and South Florida for much of the day. Isaac entered the southeastern Gulf of Mexico early on August 27, and moved more slowly toward the west-northwest and northwest. The cyclone gradually strengthened and grew even larger while moving across the Gulf of Mexico, and it became a hurricane around 1200 UTC August 28 about 85 miles southeast of the mouth of the Mississippi River (Figure 3). Isaac slowed down as it approached the coast of Louisiana, which prolonged the strong winds, dangerous storm surge, and heavy rains along the northern Gulf coast. The first landfall occurred along the southeastern coast of Louisiana at Southwest Pass on the mouth of the Mississippi River around 0000 UTC August 29 with maximum sustained winds of 80 mph. Isaac’s center then wobbled westward back over water and made a second landfall just west of Port Fourchon, Louisiana, around 0800 UTC August 29. Gradual weakening ensued once Isaac moved inland over southeastern Louisiana, and it became a tropical storm by 1800 UTC August 29 when it was located about 40 miles west-southwest of New Orleans. Isaac turned northwestward across Louisiana on August 30, and weakened to a tropical depression around 0000 UTC August 31 just after crossing into southern Arkansas. The depression turned northward and moved into southwestern Missouri late that day, and Isaac dissipated early on September 1 about 65 miles west-southwest of Jefferson City, Missouri.
Isaac’s extensive wind field led to widespread storm surge flooding along the northern Gulf of Mexico, especially in southeastern Louisiana, Mississippi, and Alabama (Figure4). The highest measured storm surge was 11.03 feet above normal tide levels at Shell Beach, Louisiana, on the southern end of Lake Borgne. Inundation levels (flooding above ground level) of 10-17 feet were prevalent in Plaquemines Parish and 8-12 feet in St. Bernard Parish. In addition, the combination of strong winds and storm surge from Isaac forced the Mississippi River to flow backwards for almost 24 hours. The storm surge traveled more than 300 miles upriver, as far as Red River Landing in northern Pointe Coupee Parish, and it caused the river to rise 8 feet in Baton Rouge, Louisiana.
Isaac produced heavy rainfall and severe flooding across portions of southern and east-central Florida, and most of extreme southwestern Alabama, southern Mississippi and southeastern Louisiana. The highest measured rainfall totals were 22.20 inches in Pascagoula, Mississippi and 20.66 inches in New Orleans, Louisiana.
Seventeen tornadoes were recorded in the United States while Isaac was a tropical cyclone. Most of the tornadoes were rated as EF-0 or EF-1, while one was rated as an EF-2. Five tornadoes occurred in Florida, all of which were rated EF-0. Four tornadoes occurred in Alabama, the strongest of which touched down as an EF-1 near the city of Samson. Mississippi had six tornadoes, with an EF-2 downing large trees and tearing nearly the entire roof off of a large house in Pascagoula. Three people were injured by an EF-1 that hit near Crandall, Mississippi. Two tornadoes also occurred in Illinois, injuring one person near the town of Franklin. At least nine additional tornadoes occurred in Illinois, Missouri, and Arkansas due to the remnants of Isaac. The strongest was an EF-2 that touched down in Corning, Arkansas, causing extensive damage to two hangars and several aircraft at the Corning Airport.
Isaac was directly responsible 5 deaths in the United States and a total damage estimated to be $2.35 billion.
Hurricane Rafael
On August 12, Rafael became a tropical storm about 230 miles south-southeast of St. Croix in the U.S Virgin Islands. Rafael was a disorganized cyclone while it moved slowly northward over the eastern Caribbean Sea during the next two days, passing between St. Martin and St. Croix around 0000 UTC October 14 with maximum winds of 50 mph. No significant damage was experienced in the US Virgin Islands.
Hurricane Sandy
Sandy passed a few hundred miles southeast of North Carolina on October 28, and by early on October 29 the hurricane moved northward when it encountered a blocking high over the North Atlantic, which prevented the cyclone from recurving out to sea. A vigorous upper-level trough moved into the southeastern United States and provided baroclinic forcing for Sandy, along with a significant decrease in vertical wind shear. These factors, in addition to the cyclone moving over warm Gulf Stream waters, caused Sandy to re-intensify early on October 29, and the hurricane reached a secondary peak intensity of 100 mph around 1200 UTC about 250 miles southeast of Atlantic City, New Jersey. Sandy accelerated northwestward later that day at forward speeds of 20-25 mph until landfall occurred. However, the hurricane moved over much cooler shelf waters and into a cold air mass located over the eastern United States and northwestern Atlantic Ocean. The colder ocean waters, interaction with frontal systems, and increasing vertical shear contributed to Sandy’s weakening, and hastened its loss of tropical characteristics. The large category 1 hurricane made the transition into a powerful extratropical cyclone by 2100 UTC October 29, about 50 miles southeast of Atlantic City. The center of Post-tropical Cyclone Sandy made landfall at about 2330 UTC near Brigantine, New Jersey, just to the northeast of Atlantic City, with an estimated intensity of 80 mph and a central pressure of 945 mb. After landfall, the cyclone slowed down and moved west-northwestward and gradually weakened as its center moved through southern New Jersey, northern Delaware and southern Pennsylvania. The center of the cyclone became ill defined over northeastern Ohio on October 31, and Sandy’s remnants moved northward to northeastward over Ontario, Canada for the next day or two before merging with a low pressure area over eastern Canada.
Sandy caused 72 direct fatalities in the United States. This is the greatest number of U.S. direct fatalities associated with a tropical cyclone outside of the southern states since Hurricane Agnes in 1972. Tables 2 records all direct deaths by country associated with Sandy in the United States.
Sandy’s impacts in the United States were widespread. Because of its tremendous size, the cyclone drove a catastrophic storm surge into the New Jersey and New York coastlines. The highest inundation was about 9 feet in areas bordering New York Harbor and Raritan Bay. Maximum inundation on the Jersey Shore and the Connecticut coastline was about 5 to 6 feet. Sandy damaged or destroyed at least 650,000 houses, with the vast majority of the damage caused by storm surge and/or waves, and about 8.5 million customers lost power. Preliminary damage estimates are near $50 billion, making Sandy the second-costliest cyclone to hit the United States since 1900, after Hurricane Katrina of 2005; it will probably be the sixth-costliest cyclone when adjusting for inflation, population, and wealth normalization factors. Figures 5 and 6 show the storm surge flooding caused by Sandy.
Sandy’s evolution into an extratropical cyclone before striking the United States produced blizzard conditions and heavy wet snow 2-3 feet deep, which made roads impassable in West Virginia and western North Carolina. The weight of the snow also caused a number of structures to collapse. Strong winds caused many downed trees, and about 271,000 people lost electricity at some point in those areas. Damage extended well inland as far west as the Ohio Valley and portions of the Midwestern United States, with the main impact being power outages. Strong winds directly associated with the post-tropical cyclone occurred as far west as Wisconsin, and generated large waves on Lake Michigan that caused some coastal flooding on its southern shore.

Table 1: Summary of activity of the 2012 Atlantic hurricane Season





Storm

Name




Class*



Dates**


Max. Winds (mph)



Min.

Pressure

(mb)



Deaths


U.S. Damage ($million)

Alberto

TS

May 19 - 22

60

995







Beryl

TS

May 26 - 30

70

992

1




Chris

H

June 18 - 22

85

974







Debby

TS

June 23 - 27

65

990

5

250

Ernesto

H

August 1 - 10

100

973

7




Florence

TS

August 3 - 6

60

1002







Gordon

H

August 15 - 20

110

965







Helene

TS

August 9 - 18

45

1004







Isaac

H

Aug 21 – Sep 1

80

965

34

2350

Joyce

TS

August 22 - 24

40

1006







Kirk

H

Aug 28 – Sep 2

105

970







Leslie

H

Aug 30 – Sep 11

80

968







Michael

MH

September 3 - 11

115

964







Nadine

H

Sep 10 – Oct 3

90

978







Oscar

TS

October 3 – 5

50

994







Patty

TS

October 11 – 13

45

1005







Rafael

H

October 12 – 17

90

969

1




Sandy

MH

October 22 – 29

115

940

147

50000

Tony

TS

October 22 – 25

50

1000






* TD - tropical depression maximum 1-minute sustained winds 38 mph or less; TS - tropical storm, winds 39-73 mph; H - hurricane, winds 74-110 mph; MH - major hurricane, winds 111 mph or higher.

** Dates based on UTC time and include tropical depression stage

Table 2: Direct deaths associated with Hurricane Sandy in the United States




State

Direct Deaths

New York

48

New Jersey

12

Connecticut

5

Pennsylvania

2

Virginia

2

New Hampshire

1

West Virginia

1

Maryland

1

Total

72

Figure 1: Tracks of Atlantic tropical storms and hurricanes that impacted the United States in 2012.



Figure 2: Rainfall totals associated with Tropical Storm Debby, 23-27 June, 2012. This map was produced by the NOAA Hydrometeorological Prediction Center.


Figure 3: Hurricane Isaac as it approached the southeastern coast of Louisiana – (a) NOAA GOES-13 visible satellite imagery at 1815 UTC August 28, 2012 (left panel) and (b) NOAA WSR-88D Doppler radar reflectivity image at 0304 UTC August 29, 2012 (right panel).


Figure 4: Flooded homes in LaPlace, Louisiana on August 30, 2012 due to storm surge created by Hurricane Isaac (photo by Michael Democker, Associated Press/The Times-Picayune).

Figure 5: Image of a rollercoaster sitting in the Atlantic Ocean in NJ after the Fun Town pier it sat on was destroyed by the stormsurge associated with Sandy (courtesy of Getty Images).




Figure 6: Storm surge penetrating the lower East Side in Manhattan, New York City, on 29 October 2012 (courtesy Twitter/nycarecs).






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