Hurricanes ... A few things you NEED to know!
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Hurricanes ... A few things you NEED to know!
by Boats Sun May 10, 2009 6:12 pm
Hurricanes ... A few things you NEED to know!
More than 50 million Americans are at risk for being caught in the path of a tropical storm or hurricane. If this is you … PLEASE BE PREPARED!
People who live inland also feel the effects of lingering storms. And storms in recent years like Hurricane Katrina that decimated New Orleans and southern Mississippi remind us how devastating tropical cyclones can be. But sociologists estimate that people remember the worst effects of a hurricane for only about seven years, the National Hurricane Center says, reinforcing the importance of always being prepared.
An average of about seven hurricanes every four years strike the United States, while about two major hurricanes (category 3 and higher) cross the U.S. coast every three years. These numbers can seem infrequent if a storm hasn't hit where you live. But anyone living within striking distance of an Atlantic Ocean or Gulf of Mexico tropical storm or hurricane is at risk.
Most deaths from tropical storms and hurricanes are water-related. Water deaths come in three forms: wave and surge flooding at and near the coast, inland flooding and flash flooding, and river or stream flooding. (Know the elevation where you live! Maximum recorded storm surge is 42 feet!)
Anticipating a Tropical Storm or a Hurricane
The Atlantic hurricane season runs from June through November; it is important to pay attention to any significant storms building in the Atlantic through summer and fall. Although the duration of hurricanes do allow time for people to prepare; they can change direction, speed, and intensity easily.
Tropical Storm and Hurricane Watches and Warnings
Four key alerts are issued that relate specifically to tropical storms and hurricanes.
Tropical Storm Watch -- Tropical storm conditions with sustained winds from 39 to 73 mph are possible in your area within the next 36 hours.
Tropical Storm Warning -- Tropical storm conditions are expected in your area within the next 24 hours.
Hurricane Watch -- Hurricane conditions (sustained winds greater than 74 mph) are possible in your area within 36 hours.
Hurricane Warning -- Hurricane conditions are expected in your area in 24 hours or less.
If you live near the ocean, you should also be aware of the following alerts.
Coastal Flood Watch -- The possibility exists for the inundation of land areas along the coast within the next 12 to 36 hours.
Coastal Flood Warning -- Land areas along the coast are expected to become, or have become, inundated by sea water above the typical tide action.
A weather radio is a good way to keep abreast of any tropical storm and/or hurricane updates!
The Saffir-Simpson Damage-Potential Scale
This scale was developed in the early 1970s by Herbert Saffir, a consulting engineer in Coral Gables, Florida, and Dr. Robert Simpson, then Director of the National Hurricane Center. The scale is based primarily on wind speeds and includes estimates of barometric pressure and storm surge associated with each of the five categories.
Category Central Pressure Winds Tidal Surge
1 -- Minimal greater than 980 mb or 28.94 in 74 to 95 mph or 64 to 83 knots 4 to 5 feet
2 -- Moderate 965 to 979 mb or 28.50 to 28.91 in 96 to 110 mph or 65 to 96 knots 6 to 8 feet
3 -- Extensive 945 to 964 mb or 27.91 to 28.47 in 111 to 130 mph or 97 to 113 knots 9 to 12 feet
4 -- Extreme 920 to 944 mb or 27.17 to 27.88 in 131 to 155 mph or 114 to 135 knots 13 to 18 feet
5 -- Catastrophic less than 920 mb or 27.17 in greater than 155 mph or 135 knots greater than 18 feet
* Category 1 [Minimal]
Damage primarily restricted to shrubbery, trees, and unanchored mobile homes; no substantial damage to other structures; some damage to poorly constructed signs, low lying roads inundated; minor damage to piers; small craft in exposed anchorages torn from moorings.
Category 2 [Moderate]
Considerable damage to shrubbery and tree foliage, some trees blown down; major damage to exposed mobile homes; extensive damage to poorly constructed signs and some damage to windows, doors and roofing materials of buildings, but no major destruction to buildings. Coastal roads and low lying escape routes inland cut off by rising water about 2 to 4 hours before landfall; considerable damage to piers and marinas; small craft in protected anchorage torn from moorings. Evacuation of some shoreline residences and low lying areas required.
Category 3 [Extensive]
Foliage torn from trees; large trees blown down; poorly constructed signs blown down; some damage to roofing, windows, and doors; some structural damage to small buildings; mobile homes destroyed. Serious flooding along the coast; many small structures near the coast destroyed; larger coastal structures damaged by battering waves and floating debris. Low lying escape routes inland cut off by rising water about 3 to 5 hours before landfall; flat terrain 5 feet or less above sea level flooded up to 8 or more miles inland.
Evacuation of low lying residences within several blocks of shoreline may be required.
Category 4 [Extreme]
Shrubs, trees, and all signs blown down; extensive damage to roofs, windows, and doors, with complete failure of roofs on many smaller residences; mobile homes demolished.
Flat terrain 10 feet or less above sea level flooded inland as far as 6 miles; flooding and battering by waves and floating debris cause major damage to lower floors of structures near the shore; low lying escape routes inland cut off by rising water about 3 to 5 hours before landfall; major erosion of beaches. Massive evacuation of all residences within 500 yards of the shore may be required, as well as of single story residences in low ground with 2 miles of the shore.
Category 5 [Catastrophic]
Trees, shrub, and all signs blown down; considerable damage to roofs of buildings, with very severe and extensive damage to winds and doors; complete failure on many roofs of residences and industrial buildings; extensive shattering of glass in windows and doors; complete buildings destroyed; small building overturned or blown away; mobile homes demolished. Major damage to lower floors of all structures less than 15 feet above sea level within 1500 feet of the shore; low lying escape routes inland cut off by rising water about 3 to 5 hours before landfall; major erosion of beaches. Massive evacuation of residential areas on low ground within 5 to 10 miles of the shore may be required.
* Information courtesy of "Hurricanes!", Peter R. Chaston.
More than 50 million Americans are at risk for being caught in the path of a tropical storm or hurricane. If this is you … PLEASE BE PREPARED!
People who live inland also feel the effects of lingering storms. And storms in recent years like Hurricane Katrina that decimated New Orleans and southern Mississippi remind us how devastating tropical cyclones can be. But sociologists estimate that people remember the worst effects of a hurricane for only about seven years, the National Hurricane Center says, reinforcing the importance of always being prepared.
An average of about seven hurricanes every four years strike the United States, while about two major hurricanes (category 3 and higher) cross the U.S. coast every three years. These numbers can seem infrequent if a storm hasn't hit where you live. But anyone living within striking distance of an Atlantic Ocean or Gulf of Mexico tropical storm or hurricane is at risk.
Most deaths from tropical storms and hurricanes are water-related. Water deaths come in three forms: wave and surge flooding at and near the coast, inland flooding and flash flooding, and river or stream flooding. (Know the elevation where you live! Maximum recorded storm surge is 42 feet!)
Anticipating a Tropical Storm or a Hurricane
The Atlantic hurricane season runs from June through November; it is important to pay attention to any significant storms building in the Atlantic through summer and fall. Although the duration of hurricanes do allow time for people to prepare; they can change direction, speed, and intensity easily.
Tropical Storm and Hurricane Watches and Warnings
Four key alerts are issued that relate specifically to tropical storms and hurricanes.
Tropical Storm Watch -- Tropical storm conditions with sustained winds from 39 to 73 mph are possible in your area within the next 36 hours.
Tropical Storm Warning -- Tropical storm conditions are expected in your area within the next 24 hours.
Hurricane Watch -- Hurricane conditions (sustained winds greater than 74 mph) are possible in your area within 36 hours.
Hurricane Warning -- Hurricane conditions are expected in your area in 24 hours or less.
If you live near the ocean, you should also be aware of the following alerts.
Coastal Flood Watch -- The possibility exists for the inundation of land areas along the coast within the next 12 to 36 hours.
Coastal Flood Warning -- Land areas along the coast are expected to become, or have become, inundated by sea water above the typical tide action.
A weather radio is a good way to keep abreast of any tropical storm and/or hurricane updates!
The Saffir-Simpson Damage-Potential Scale
This scale was developed in the early 1970s by Herbert Saffir, a consulting engineer in Coral Gables, Florida, and Dr. Robert Simpson, then Director of the National Hurricane Center. The scale is based primarily on wind speeds and includes estimates of barometric pressure and storm surge associated with each of the five categories.
Category Central Pressure Winds Tidal Surge
1 -- Minimal greater than 980 mb or 28.94 in 74 to 95 mph or 64 to 83 knots 4 to 5 feet
2 -- Moderate 965 to 979 mb or 28.50 to 28.91 in 96 to 110 mph or 65 to 96 knots 6 to 8 feet
3 -- Extensive 945 to 964 mb or 27.91 to 28.47 in 111 to 130 mph or 97 to 113 knots 9 to 12 feet
4 -- Extreme 920 to 944 mb or 27.17 to 27.88 in 131 to 155 mph or 114 to 135 knots 13 to 18 feet
5 -- Catastrophic less than 920 mb or 27.17 in greater than 155 mph or 135 knots greater than 18 feet
* Category 1 [Minimal]
Damage primarily restricted to shrubbery, trees, and unanchored mobile homes; no substantial damage to other structures; some damage to poorly constructed signs, low lying roads inundated; minor damage to piers; small craft in exposed anchorages torn from moorings.
Category 2 [Moderate]
Considerable damage to shrubbery and tree foliage, some trees blown down; major damage to exposed mobile homes; extensive damage to poorly constructed signs and some damage to windows, doors and roofing materials of buildings, but no major destruction to buildings. Coastal roads and low lying escape routes inland cut off by rising water about 2 to 4 hours before landfall; considerable damage to piers and marinas; small craft in protected anchorage torn from moorings. Evacuation of some shoreline residences and low lying areas required.
Category 3 [Extensive]
Foliage torn from trees; large trees blown down; poorly constructed signs blown down; some damage to roofing, windows, and doors; some structural damage to small buildings; mobile homes destroyed. Serious flooding along the coast; many small structures near the coast destroyed; larger coastal structures damaged by battering waves and floating debris. Low lying escape routes inland cut off by rising water about 3 to 5 hours before landfall; flat terrain 5 feet or less above sea level flooded up to 8 or more miles inland.
Evacuation of low lying residences within several blocks of shoreline may be required.
Category 4 [Extreme]
Shrubs, trees, and all signs blown down; extensive damage to roofs, windows, and doors, with complete failure of roofs on many smaller residences; mobile homes demolished.
Flat terrain 10 feet or less above sea level flooded inland as far as 6 miles; flooding and battering by waves and floating debris cause major damage to lower floors of structures near the shore; low lying escape routes inland cut off by rising water about 3 to 5 hours before landfall; major erosion of beaches. Massive evacuation of all residences within 500 yards of the shore may be required, as well as of single story residences in low ground with 2 miles of the shore.
Category 5 [Catastrophic]
Trees, shrub, and all signs blown down; considerable damage to roofs of buildings, with very severe and extensive damage to winds and doors; complete failure on many roofs of residences and industrial buildings; extensive shattering of glass in windows and doors; complete buildings destroyed; small building overturned or blown away; mobile homes demolished. Major damage to lower floors of all structures less than 15 feet above sea level within 1500 feet of the shore; low lying escape routes inland cut off by rising water about 3 to 5 hours before landfall; major erosion of beaches. Massive evacuation of residential areas on low ground within 5 to 10 miles of the shore may be required.
* Information courtesy of "Hurricanes!", Peter R. Chaston.
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