Huricane Information

NOAA PREDICTS ABOVE NORMAL 2007 NORTH ATLANTIC HURRICANE SEASON

Residents in Hurricane Prone Areas are Urged to Make Preparations

May 22, 2007 — Experts at the NOAA Climate Prediction Center are projecting a 75 percent chance that the Atlantic Hurricane Season will be above normal this year—showing the ongoing active hurricane era remains strong. With the start of the hurricane season upon us, NOAA recommends those in hurricane-prone regions to begin their preparation plans.

Last year, seasonal hurricane predictions proved to be too high when an unexpected El Niño rapidly developed and created a hostile environment for Atlantic storms to form and strengthen. When storms did develop, steering currents kept most of them over the open water and away from land.

TROPICAL STORM SYSTEMS

Tropical depressions, tropical storms and hurricanes are low pressure areas that develop in the tropical regions of the ocean (between 20 degrees N latitude and the equator). These storms are masses of thunderstorms that organize and begin to rotate. These systems, in order of intensity, are called depressions (winds between 25 and 38 mph), tropical storms (winds between 39 and 73 mph) and hurricanes (winds of 74 mph or greater).

The National Weather Service tracks these storms on charts during hurricane season, June 1 through Nov. 30, using the following symbols.

• A tropical depression, the lowest intensity, is given a number once it has a counterclockwise spin and winds of 38 mph or less.

• When wind speeds reach 39 mph and the storm is given a name from a pre-determined list, a tropical storm is born. While a tropical storm does not produce a high storm surge, its thunderstorms can still pack a dangerous and deadly punch. In 1972, Agnes was only a tropical storm when it dropped torrential rains that led to devastating floods in Pennsylvania, Maryland and Virginia. Sixteen people died in Virginia and damage was estimated at $222 million.

• A hurricane is the most intense tropical event, with five categories and winds ranging from 74 mph to 155 mph or greater. Storm surge is a major concern with hurricanes. The extremely high winds cause ocean water to pile up, creating higher than normal sea levels with waves up to 40 feet in open water. High sea levels and shallow waters can devastate a coastline and bring ocean water miles inland.

A hurricane's bands of thunderstorms produce torrential rains and sometimes tornadoes. A foot or more of rain could fall in less than a day, causing flash floods and mudslides. Large rivers in the hurricane's path might still be flooding for days after the storm has passed. The storm's driving winds can topple trees, utility poles and damage buildings. Communication and electricity might be lost for days and roads are often impassable due to fallen trees and debris.

SAFFIR SIMPSON HURRICANE SCALE

The Saffir-Simpson Hurricane Scale is a 1-5 rating based on the hurricane's present intensity. This is used to give an estimate of the potential property damage and flooding expected along the coast from a hurricane landfall. Wind speed is the determining factor in the scale, as storm surge values are highly dependent on the slope of the continental shelf and the shape of the coastline, in the landfall region. Note that all winds are using the U.S. 1-minute average.

• Category 1 Hurricane — Winds 74-95 mph (64-82 kt or 119-153 km/hr). Storm surge generally 4-5 ft above normal. No real damage to building structures. Damage primarily to unanchored mobile homes, shrubbery, and trees. Some damage to poorly constructed signs. Also, some coastal road flooding and minor pier damage. Hurricane Lili of 2002 made landfall on the Louisiana coast as a Category One hurricane. Hurricane Gaston of 2004 was a Category One hurricane that made landfall along the central South Carolina coast.

• Category 2 Hurricane — Winds 96-110 mph (83-95 kt or 154-177 km/hr). Storm surge generally 6-8 feet above normal. Some roofing material, door, and window damage of buildings. Considerable damage to shrubbery and trees with some trees blown down. Considerable damage to mobile homes, poorly constructed signs, and piers. Coastal and low-lying escape routes flood 2-4 hours before arrival of the hurricane center. Small craft in unprotected anchorages break moorings. Hurricane Frances of 2004 made landfall over the southern end of Hutchinson Island, Florida as a Category Two hurricane. Hurricane Isabel of 2003 made landfall near Drum Inlet on the Outer Banks of North Carolina as a Category 2 hurricane.

• Category 3 Hurricane — Winds 111-130 mph (96-113 kt or 178-209 km/hr). Storm surge generally 9-12 ft above normal. Some structural damage to small residences and utility buildings with a minor amount of curtainwall failures. Damage to shrubbery and trees with foliage blown off trees and large trees blown down. Mobile homes and poorly constructed signs are destroyed. Low-lying escape routes are cut by rising water 3-5 hours before arrival of the center of the hurricane. Flooding near the coast destroys smaller structures with larger structures damaged by battering from floating debris. Terrain continuously lower than 5 ft above mean sea level may be flooded inland 8 miles (13 km) or more. Evacuation of low-lying residences with several blocks of the shoreline may be required. Hurricanes Jeanne and Ivan of 2004 were Category Three hurricanes when they made landfall in Florida and in Alabama, respectively.

• Category 4 Hurricane — Winds 131-155 mph (114-135 kt or 210-249 km/hr). Storm surge generally 13-18 ft above normal. More extensive curtainwall failures with some complete roof structure failures on small residences. Shrubs, trees, and all signs are blown down. Complete destruction of mobile homes. Extensive damage to doors and windows. Low-lying escape routes may be cut by rising water 3-5 hours before arrival of the center of the hurricane. Major damage to lower floors of structures near the shore. Terrain lower than 10 ft above sea level may be flooded requiring massive evacuation of residential areas as far inland as 6 miles (10 km). Hurricane Charley of 2004 was a Category Four hurricane made landfall in Charlotte County, Florida with winds of 150 mph. Hurricane Dennis of 2005 struck the island of Cuba as a Category Four hurricane.

• Category 5 Hurricane — Winds greater than 155 mph (135 kt or 249 km/hr). Storm surge generally greater than 18 ft above normal. Complete roof failure on many residences and industrial buildings. Some complete building failures with small utility buildings blown over or away. All shrubs, trees, and signs blown down. Complete destruction of mobile homes. Severe and extensive window and door damage. Low-lying escape routes are cut by rising water 3-5 hours before arrival of the center of the hurricane. Major damage to lower floors of all structures located less than 15 ft above sea level and within 500 yards of the shoreline. Massive evacuation of residential areas on low ground within 5-10 miles (8-16 km) of the shoreline may be required. Only 3 Category Five Hurricanes have made landfall in the United States since records began: The Labor Day Hurricane of 1935, Hurricane Camille (1969), and Hurricane Andrew in August, 1992. The 1935 Labor Day Hurricane struck the Florida Keys with a minimum pressure of 892 mb--the lowest pressure ever observed in the United States. Hurricane Camille struck the Mississippi Gulf Coast causing a 25-foot storm surge, which inundated Pass Christian. Hurricane Andrew of 1992 made landfall over southern Miami-Dade County, Florida causing 26.5 billion dollars in losses--the costliest hurricane on record. In addition, Hurricane Gilbert of 1988 was a Category Five hurricane at peak intensity and is the strongest Atlantic tropical cyclone on record with a minimum pressure of 888 mb.

NAMES FOR ATLANTIC BASIN TROPICAL CYCLONES

2006 Alberto Beryl Chris Debby Ernesto Florence Gordon Helene Isaac Joyce Kirk Leslie Michael Nadine Oscar Patty Rafael Sandy Tony Valerie William

2007 Andrea Barry Chantal Dean Erin Felix Gabrielle Humberto Ingrid Jerry Karen Lorenzo Melissa Noel Olga Pablo Rebekah Sebastien Tanya Van Wendy

2008 Arthur Bertha Cristobal Dolly Edouard Fay Gustav Hanna Ike Josephine Kyle Laura Marco Nana Omar Paloma Rene Sally Teddy Vicky Wilfred

2009 Ana Bill Claudette Danny Erika Fred Grace Henri Ida Joaquin Kate Larry Mindy Nicholas Odette Peter Rose Sam Teresa Victor Wanda

2010 Alex Bonnie Colin Danielle Earl Fiona Gaston Hermine Igor Julia Karl Lisa Matthew Nicole Otto Paula Richard Shary Tomas Virginie Walter

2011 Arlene Bret Cindy Don Emily Franklin Gert Harvey Irene Jose Katia Lee Maria Nate Ophelia Philippe Rina Sean Tammy Vince Whitney

BASIC HURRICANE SAFETY ACTIONS

• Know if you live in an evacuation area. Know your home's vulnerability to storm surge, flooding and wind. Have a written plan based on this knowledge.
• At the beginning of hurricane season (June 1st), check the supplies for your disaster supply kit, replace batteries and use food stocks on a rotating basis.
• During hurricane season, monitor the tropics.
• Monitor NOAA Weather Radio. It is an excellent / official source for real-time weather information and warnings.
• If a storm threatens, heed the advice from local authorities. Evacuate if ordered.
• Execute your family plan

WATCH vs. WARNING - KNOW THE DIFFERENCE

• A HURRICANE WATCH issued for your part of the coast indicates the possibility that you could experience hurricane conditions within 36 hours.
  This watch should trigger your family's disaster plan, and protective measures should be initiated, especially those actions that require extra time such as securing a boat, leaving a barrier island, etc.
• A HURRICANE WARNING issued for your part of the coast indicates that sustained winds of at least 74 mph are expected within 24 hours or less.
  Once this warning has been issued, your family should be in the process of completing protective actions and deciding the safest location to be during the storm.

EVACUATION ROUTES

• The Atlantic hurricane season runs from June through November. During that period, eastern Virginia is especially at risk for a major storm.

• Evacuations are planned to be conducted in two phases:
  • Phase One (24 to 14 hours before the start of tropical storm-force winds)
  • Phase Two (14 hours before the start of tropical storm-force winds)

• For more hurricane information for Virginia, go to VDOT's hurricane evacuation guide site.