Hurricanes: What do You Know?

NOAA issues seasonal hurricane outlooks that you will find on the National Hurricane Center Website and so do private forecasters like Dr. Bill Gray at Colorado State University, AccuWeather, and the NCSU Tropical Cyclone Prediction Team. All of these forecasts are for the entire Atlantic basin which includes the Atlantic Ocean, the Caribbean Sea, and the Gulf of Mexico so they really don't tell you much about any one spot. Check the long term statistical probability of a hurricane landfall.

A Tropical Wave is a region of low pressure and cloudiness that moves from east to west in the tropics. These are a usual part of tropical weather just as we talk about highs and lows moving across the US.

A Tropical Disturbance is when thunderstorms develop and last for more than a day within a tropical wave. These are common.

If the tropical disturbance shows a circulation with the thunderstorms becoming organized it is called a Tropical Depression and given a number for tracking purposes. We show it as an "L" on our weather maps. At this point more attention is given to it as something that may develop further.

If the winds in a tropical disturbance exceed 38mph it becomes a Tropical Storm and it is then given a name from a pre-selected list. The winds in a tropical storm may range from 38mph to 73mph.

If the tropical storm increases wind speed to 74mph or greater it is then called a Hurricane.

Tropical systems can form in several days or just one day. The water temperature needs to be at least 80 degrees in the top 150 feet of the ocean. The water temperature at the beach is not enough to influence a hurricane since the water is so shallow. Winds in the atmosphere must not change too much in direction and speed otherwise a storm would be shredded apart. As warm ocean water evaporates and condenses to form clouds, heat feeds the developing thunderstorms. The thunderstorms act together as they circulate to form a tropical storm.

Typical hurricanes are about 300 miles wide but they vary in size. The eye of the storm is relatively calm and between 20 to 40 miles across. The eyewall surrounding the eye has the highest winds. Hurricane force winds can extend outward 25 to 150 miles, while tropical storm force wind can stretch out as far as 300 miles. Outer rainbands that feed the storm can be 50 to 300 miles long. The right side of a hurricane path is the most dangerous when it comes to wind, flooding, and tornadoes. Do not focus on the eye or exact forecast track- Danger exists in a large area based on the storm size and based on the uncertainty in forecasting. Every storm is different based on the wind speed, the motion, the track the eye size, the hurricane wind radius, and the amount of rainfall. You can not just compare two hurricanes on any one of the above.

As Hurricanes or Tropical Storms approach land, first Watches are issued, then Warnings. The Watches tell you that the effects of either the Tropical Storm or Hurricane are possible within 36 hours while the Warnings tell you that the storm is likely to affect your area within 24 hours. During the Watch is when you make advance plans for safety and shelter. When the Warning is issued you must take immediate action for personal safety.

Technology and communication have helped to dramatically reduce hurricanes deaths in the last half century but as population and housing grow along the coastal areas we see a major increase in the dollar amount of damage. With higher population density the potential for major loss of life increases because not everyone may be able to escape harm in short notice. It is important to know that the 1960s through the 1990s were fairly quiet hurricane seasons compared to the 1930s and 1940s. It looks like we are returning to more active seasons.

A category 1 hurricane has winds between 74 and 95 mph. Damage is minimal. Expect some coastal road flooding, minor pier damage, damage to unanchored mobile homes, trees and shrubs. Danny in July of 1997 was a category one but its biggest problem was from the more than 2 feet of rain that fell.

A category 2 hurricane creates moderate damage with winds of 96-110mph. It produces damage to roofing, doors and windows, and mobile homes. Small craft moorings may break in unprotected water, and low-lying coastal escape routes flood. In August of 1995 Erin made landfall as a category 2.

A category 3 hurricane has winds of 111-130 mph. Complete roofs may fail, mobile homes are destroyed, coastal flooding carries destructive debris inland. Opal in 1995, Ivan in 2004 and Dennis in 2005 were marginal category 3 at landfall while Frederic in 1979 was a high category 3 storm. Katrina in 2005 was also a high category 3 at landfall based on the wind even though storm surge along the Mississippi coast was more like that from a category 5.

A category 4 hurricane produces extreme damage with winds of 131-155mph. Major beach erosion and major damage to beachside residences is common. Land that is no more than 10 feet above sea level may be flooded and require evacuation as far inland as 10 miles.

A category 5 hurricane is catastrophic. The winds exceed 155mph. Massive evacuation within 5-10 miles of the coast may be needed. Major damage occurs to all structures on the coastline. Complete roof failure is seen on many homes and businesses. Dean in 2007 was a category 5 in the Yucatan, Camille in 1969 was a category 5 in southern Mississippi and so was Andrew in south Florida in 1992.

Some people wonder why not just drop a bomb on a hurricane to weaken it. Part of the answer is that an average hurricane has the equivalent power each day of hundreds and hundreds of atomic bombs. Take at look at these rough comparisons on energy. If you release that much radiation in the atmosphere we are all in trouble. The other reason hurricane modification is tricky is because hurricanes happen in international waters and if a storm grows worse to strike another country there would be political problems. One final reason modifying hurricanes is not a good idea is because they are a vital part of the atmospheric processes to keep the Earth in balance. If you remove a part of the chain something worse could happen.

Some people wonder if increased hurricane activity is due to global warming. Global warming or climate change is a very slow process. The main cause of more hurricanes seems to be 20-30 year cycles in overall hurricane activity. The 1950s through the 1990s were much quieter than the 1930s and 1940s but many people have forgotten that. According to NOAA we are entering the increased activity portion of the cycle. Katrina occurred in this cycle as a rare exception where hundreds of people died. Realize that most Katrina deaths occurred after the storm passed when levees failed. After the active recent hurricane seasons we find the central Gulf Coast with a lot of lingering storm debris in our waterways and along the coastline. NOAA tries to keep track of the marine debris cleanup.

Tropical Storm names are alphabetical and agreed upon by an international organization of meteorologists in the World Meteorological Organization. Names alternate male and female, and represent names common in the countries where tropical storms may strike. There are no names used starting with Q, U, X, Y, Z because there are fewer common names starting with these letters. There are 6 years worth of names and the lists are recycled every 6 years. Only when a storm is very destructive is the name retired. In 2005 when we ran through all the names we used the Greek alphabet starting with Alpha, Beta, Gamma....

For 2008 the Atlantic/Caribbean/Gulf names are...

Read about hurricanes that have affected the Mobile-Pensacola area from the Mobile National Weather Service, and  University of South Alabama Coastal Weather Research Center.

Most of Earth’s surface is water and prior to satellites the formation of many tropical systems went undetected. In the 1960s satellites first gave us a view of developing tropical storms. In the 1970s radars presented a different perspective of tropical storms along the coastlines. We were clearly able to see rainbands and better understand what happens beneath the cloud canopy of a hurricane. Since then, meteorologists have developed sophisticated computer models to aid in projecting hurricane and tropical storm paths. These models are not perfect. They are only as good as our understanding of the atmosphere and the information that goes into them.

A big problem in hurricane forecasting is that there are very few data sensors over the oceans. We do not get hourly reports of temperature, wind, pressure and humidity as we do at hundreds of locations across the US. Satellites show the big picture but it is the details under the clouds that elude forecasters. As tropical storms grow and pose any threat to land, the US sends Hurricane Hunter aircraft into them to take readings. Even with the Hurricane Hunters we still don’t get a frequent, detailed measurement of approaching hurricanes. In more powerful or threatening storms NOAA sends other research aircraft into storms as well in attempts to learn more about them.

Watch video of a flight Chief Meteorologist Alan Sealls took with the Hurricane Hunters into Tropical Storm Gabrielle.

Official hurricane forecasts for the US come from the National Hurricane Center, north of Miami. Meteorologists there focus their attention on the tropics. Using computer models, aircraft reports, data from buoys, satellite and radar, these experts have in recent years been able to project hurricane eye landfall to within 220 miles 3 days in advance. At 24 hours the accuracy is within 70 miles. This might not sound like accuracy to the average person but when you consider the size of the oceans and the complexity of the atmosphere, it is remarkable that forecasts can be this accurate. You can never expect the eye location to be so precise that you can disregard the hazards of an approaching tropical storm. Even when a prediction is right on target it is not just the eye of a storm where the weather can be deadly. Forecasting will never be 100% accurate so always be ready for change and updates. Along the central gulf coast we rely on the National Weather Service Office located at the Mobile Regional airport to issue local tropical storm advisories and bulletins.

Keep up with forecasts on TV, Internet and radio, as well as on your NOAA Weather Radio. At WKRG News5 we will give you frequent updates, and you can see our Doppler Radar along with satellite loops on wkrg.com. You can follow current storms or view historic storms in our Hurricane Center. When tropical systems approach we do our best to give you the clearest picture of what might happen. However, no computer or person can guarantee tomorrow’s weather. It is up to you to not put yourself in a position where you have no choices for safety when bad weather nears. If you wait until the last minute to take action, you increase risk. Stay safe!

Consider strengthening the building you live or work in. Find excellent tips and instructions from FLASH, the Federal Alliance for Safe Homes. Another organization with great information on safeguarding buildings and homes is the Institute for Business and Home Safety. Don't forget to have a safety plan for your pets. Here's a list from the Humane Society of the US.

There is a whole lot more to learn from National Hurricane Center Hurricane Awareness Website or NASA website with information for kids. Kids and grownups can learn more about hurricanes at FEMA's website for kids FEMA hurricanes and at the NASA Hurricane Website.

• Assemble a disaster supplies kit.
• Batteries, batteries, batteries. Battery-powered radio and flashlight.
• Canned Food (non perishable food) and a manual can opener. Cash and credit cards. Charcoal for grills.
• Diapers, formula and infant items.
• Elderly people have special needs.
• First aid kit and essential medications.
• Gas - fill your car's gas tank. Also fill your gas grill or portable stove for alternative cooking devices.
• Home - secure your home before the storm threatens (plywood, shutters, and/or protective window film, plastic sheeting, nails, etc.)
• Identify ahead of time where you could go if you are told to evacuate.
• June 1 - November 30 hurricane season lasts six months.
• Keep handy the telephone numbers of several places - a friend's home in another town, a motel, or a shelter.
• Listen to NOAA Weather Radio or local radio or TV stations for evacuation instructions.
• Medications - bring extra supplies and a list of what you're taking.
• Never use candles - they are a fire hazard.
• Outdoor objects such as lawn furniture, toys, and garden tools need to be brought inside.
• Pets are not allowed in Red Cross shelters. Have a plan for your family pet.
• Quiet games, books, playing cards and favorite toys for children.
• Refrigerator - turn refrigerator and freezer to coldest settings. Open only when absolutely necessary and close quickly.
• Sleeping bags, blankets, pillows to use at the shelter or if you must evacuate.
• Tornadoes can happen during a hurricane and after it passes over.
• Utilities - Teach family members how and when to turn off gas, electricity, and water.
• Valuables - store valuables and personal papers in a waterproof container on the highest level of your home.
• Water - at least three gallons of water per person. Fill your own clean jugs, you don't have to buy water!
• Xtra everything - medications, batteries, cash, water, gas.
• Yard - Bring in outdoor objects such as lawn furniture, toys, and garden tools
• Ziplock bags - keep important phone numbers, medical and pet information, and important papers in a zipper lock bag.

We are in hurricane territory along the Gulf Coast. Make no mistake, this is where tropical storms visit and we've all got to be prepared. Is your home in order? Do you have a list of all of your possessions? Do you know when to leave and where to go when a hurricane gets close? Using the links below, you'll find surge maps, evacuation zones, and evacuation routes for central Gulf coast coastal counties. The effects of tropical storms and hurricanes extend inland so we all need to plan ahead.

Mobile and Baldwin Counties
Jackson County, MS
Harrison County, MS
Escambia County, FL
Santa Rosa County, FL
Okaloosa County, FL

Florida Department of Financial Services has excellent information on insurance against storms for all of us consumers, in any state. There's a wealth of other information on wkrg.com. You can download a hurricane tracking chart, or other hurricane booklets like a complete Hurricane Guide that's great for teachers and kids. You can impress your friends with hurricane facts and trivia, just check out the Hurricane FAQ