HURRICANE MYTHS AND MISCONCEPTIONS

Hurricanes Generally Occur During Hurricane Season, But Can Occur at Other Times of the Year

• Myth: Hurricanes/tropical storms strike only during the official hurricane season of June 1 through November 30.
• Truth: Hurricanes/tropical storms sometimes occur before or after the hurricane season. For example, Tropical Storm Anna and Hurricane Lili occurred in April 2003 and late December 1984, respectively. Likewise, in January 2006, Hurricane Zeta (though no threat to land) loomed in the Atlantic Ocean.

Weather Conditions Can Change Quickly — Don’t Wait until the Last Minute to Evacuate

• Myth: My area is under an evacuation order, but the weather looks great right now so I can wait until the weather gets bad before I evacuate.
• Truth: This can be one of the most dangerous decisions you can make. You must realize that predicting that where a storm is going — its track — has a degree of uncertainty, and waiting until the last minute can leave you with no place to go to escape a storm's fury (if the storm does not behave according to forecast). Evacuation orders are given based on the best information available and are issued early enough to allow sufficient time for people to get to shelters. Don’t take chances with your life. Gather your important papers, your hurricane survival kit, prescriptions and cash (as you may not be able to use credit cards after the storm). Secure your home and leave as quickly and safely as possible.

The Size of a Hurricane Does Not Necessarily Correlate with Its Intensity

• Myth: The larger a tropical cyclone is, the more intense it will be.
• Truth: No. There is very little association between hurricane intensity (either measured by maximum sustained winds or by central pressure) and size (measured by radius of tropical storm force winds). Hurricane Andrew is a good example of a very intense tropical cyclone (922 mb central pressure and 165 mph sustained winds at landfall in Florida) that was also relatively small (tropical storm force winds extended out only about 90-miles from the center). Likewise, intense rainfall is not directly related to the wind speed of tropical cyclones. In fact, some of the greatest rainfall amounts occur from weaker storms that drift slowly or stall over an area.

It Is Dangerous To Venture Out Into the Eye of the Storm

• Myth: It is safe to go outside during the “eye” of the hurricane.
• Truth: It is not safe to go outside during the “eye” of the hurricane. You have no way of knowing how long the light winds will last. Strong winds will return very quickly from the opposite direction. STAY INDOORS.

Inland Areas Are Also at Risk from Hurricanes

• Myth: Only coastal areas are at risk from hurricanes.
• Truth: It is important to remember that a hurricane is not just a coastal event. The strong winds, heavy rains, tornadoes and inland flooding from weakening tropical systems can spread well inland and cause tremendous damage. Tropical Storm Allison (2001), for example, produced extremely heavy rainfall (nearly 37-inches) and catastrophic floods in the Houston, Texas area. Allison then acquired subtropical characteristics and continued to produce heavy rainfall and flooding near its track from Louisiana eastward to North Carolina, and then northward along the U.S. east coast to Massachusetts. Forty-one deaths were directly related to the heavy rain, flooding, tornadoes and high surf. Damage estimates reported by the Federal Emergency Management Agency were near $5 billion dollars, with approximately $4.8 billion dollars in the Houston metropolitan area alone. Other hurricanes that caused extensive inland damage included: Hurricane Floyd (1999), Tropical Storm Alberto (1994), Tropical Storm Claudette (1979) and Hurricane Agnes (1972).

Hurricanes Dissipate over Land Because they are No Longer Fueled by the Ocean’s Heat and Moisture

• Myth: It is the friction over land that contributes toward the dissipation of tropical cyclones.
• Truth: No. During landfall, the increased friction over land acts — somewhat contradictory — to both decrease the sustained winds and also to increase the gusts felt at the surface. The sustained (one minute or longer average) winds are reduced because of the dampening effect of larger roughness over land (i.e. bushes, trees and houses over land versus a relatively smooth ocean). The gusts are stronger because turbulence increases and acts to bring faster winds down to the surface in short (a few seconds) bursts. However, after just a few hours, a tropical cyclone over land will begin to weaken rapidly — not because of friction — but because the storm lacks the moisture and heat sources that the ocean provided. This depletion of moisture and heat diminishes the tropical cyclone's ability to produce thunderstorms near the storm center. Without this convection, the storm rapidly fills.

Hurricane Force Winds are Stronger and More Sustained than Other Types of Wind

• Myth: Winds from a hurricane can not be much worse than that experienced during a summer thunderstorm.
• Truth: While summer thunderstorms can produce wind gusts in excess of 60 miles per hour, the winds of a major hurricane can reach twice that speed — or even faster — and will be sustained for hours, much longer than a brief thunderstorm. Even 50 mph winds can do some damage, but the wind force increases at a much faster rate as the wind speed increases. Each time the wind speed is doubled, the wind force increases by a factor of four! If you triple the wind speed the force increases by NINE times! That means a 100 mph winds (a Category 2 hurricane) has four times the force of a 50 mph wind, and a 150 mph wind (a Category 4 hurricane) is nine times as strong as that of a 50 mph wind! Minimum hurricane strength winds of 74 mph have the ability to drive a piece of 2x4 lumber through a reinforced concrete wall four inches thick! A Category 2 hurricane, with winds of 96 to 110 miles per hour, can do considerable damage to roof structures and topple trees.

All of the Doors and Windows Should Be Closed (and Shuttered) Throughout the Duration of the Hurricane.

• Myth: During a hurricane are you supposed to have the windows and doors on the storm side closed and the windows and doors on the lee side open.
• Truth: No! All of the doors and windows should be closed (and shuttered) throughout the duration of the hurricane. The pressure differences between inside your house and outside in the storm do not build up enough to cause any damaging explosions. (No house is built airtight.) The winds in a hurricane are highly turbulent and an open window or door — even if in the lee side of the house — can be an open target to flying debris. All exterior windows should be boarded up with either wooden or metal shutters. On a related note, you should NOT tape your windows in preparation for a hurricane — it is a waste of time, effort and tape. It offers little strength to the glass and NO protection against flying debris. After the storm passes you will spend many a hot summer afternoon trying to scrape the old, baked-on tape off your windows (assuming they weren't shattered). Once a Hurricane Warning has been issued you would be better off spending your time putting up shutters over doors and windows.

Taking Some Basic Precautions Can Significantly Reduce Damage from a Storm

• Myth: I don’t need to prepare my house? When the big one comes, it’s going to be destroyed anyway.
• Truth: While a hurricane's winds can destroy even the most solidly built structures, taking some basic precautions can significantly reduce damage from a storm. Damage assessment photos of areas devastated by hurricanes will often show one house standing, while a neighbor's lies in ruins. The difference? The owners of the house in good shape took some basic precautions to safeguard their property. Shuttering windows, bracing garage and entry doors and bringing in yard items can mean the difference between destruction and minor damage.

Section of coastline before and after Hurricane Hugo's storm surge hit Folly Beach, SC.

Storm Surge Is Water that Is Pushed Toward the Shore by the Force of the Winds Swirling Around the Storm

• Myth: The low pressure in the tropical cyclone center causes storm surge.
• Truth: No. Many people assume that the partial vacuum at the center of a tropical cyclone allows the ocean to rise up in response, thus causing the destructive storm surges as the cyclone makes landfall. This effect, in a 900-millibar central pressure tropical cyclone, would only be 1 meter (3 feet). The total storm surge for a tropical cyclone of this intensity can be from 6 to 10 meter (19 to 33 feet), or more. Most (more than 85 percent) of the storm surge is caused by winds pushing the ocean surface ahead of the storm on the right side of the track (left side of the track in the Southern Hemisphere). Note also that individual storm surges are also dependent upon the coastal topography, angle of incidence of landfall, speed of tropical cyclone motion, as well as the wind strength.

Storm surge along a shallow and steep sloping shoreline.

Storm Surge Can Impact Areas Far Inland

• Myth: Storm surge will not impact me, I am located two whole blocks from the beach!
• Truth: Storm surge is a wind driven dome of water that rushes inland ahead of, and to the right of, the center of a hurricane. The dome can reach to 25-30 feet in the right place on the coastline, in a Category 5 land falling hurricane! It will NOT stop in a block, or two blocks, or in some cases, for miles! The NOAA National Hurricane Center uses its SLOSH (Sea, Lake, and Overland Surges from Hurricanes) model to predict surge inundation. Emergency managers use the data from the SLOSH model to determine which areas must be evacuated for storm surge. Storm surge also affects rivers and inland lakes, potentially increasing the area that must be evacuated.

It Is Not Always Safe to Evacuate Up In Tall Buildings

• Myth: The storm surge is only going to be 15 or 20 feet at worst. My condo is on an upper floor. I’m riding the storm out here.
• Truth: Vertical evacuation, or escaping the rising storm surge by going to the upper stories of a building, is not always a good idea. Wind speeds increase the higher you go, so you may be evacuating into a more dangerous place. Plus, the high winds and water will make getting help to you nearly impossible after the storm passes.