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Fri May 31, 2013
Eastern North Carolina's Hurricane Outlook for 2013
If you’ve lived in eastern North Carolina for any length of time, saying the word “hurricane” evokes memories of past storms like Floyd, Isabel, Fran or Bertha. The powerful winds and torrential downpours during a hurricane can be stressful for native North Carolinians and downright terrifying for newcomers. The National Oceanic and Atmospheric Administration’s Climate Prediction Center have released predictions for the 2013 Atlantic hurricane season forecasting an active or extremely active season. Meteorologist John Cole is with the National Weather Service Office in Newport.
“ Some of the numbers that they put out were 13 to 20 named storms, seven to 11 hurricanes, and three to six major hurricanes and that would be hurricanes with sustained winds over 11o mph.”
Hurricanes are low pressure systems in the atmosphere that rotate counter-clock wise. Most hurricanes originate off the coast of Africa, generally out of an easterly wave. Approximately 100 waves come off the coast each season, and about 10 percent develop into tropical storms or hurricanes. Warmer-than-average water temperatures in the tropical Atlantic Ocean and Caribbean Sea, as well as the absence of hurricane suppressing El Niño conditions are some of the reasons why this year’s season is likely to be more active.
“We’re expecting a wetter and more active west African monsoon. The upper level easterly winds are expected to expand westward. We’re expecting weaker trade winds, those weaker trade winds don’t allow for any sheer in the lower levels. Also, there’s something called an African easterly jet… that’s expected to be in a favorable position for generating low pressure areas off the coast of Africa.”
Hurricanes are categorized to show the intensity of wind speed, central barometric pressure, and storm surge. The Saffir-Simpson scale is a 1-5 rating used to measure the hurricane’s strength. It's used to give an estimate of the potential property damage and flooding expected along the coast- from a hurricane landfall. A category 1 or 2 hurricane is generally thought of as a fairly weak hurricane. But in 1999, Hurricane Floyd produced heavy torrential rain in eastern North Carolina, dumping more rain on an area already saturated by Hurricane Dennis just weeks before. The rain caused widespread flooding over several weeks, resulting in 35 fatalities and about 4 billion dollars in damages in North Carolina alone.
“It was a category 2 hurricane when it made landfall. But then the rainfall affects inland, along the river basins and in the river basins caused disastrous flooding which could be compared to anywhere from a 100 year flood to a 500 year flood. It’s that rare of an occurrence.”
Being prepared before a flood takes place makes all the difference. You can minimize flood damage by storing valuables in the attic or in a second story if possible. Keep household chemicals above the flood level. Make sure that underground storage tanks are fully sealed and secure. Also, move vehicles, RVs, trailers and lawnmowers to higher ground. During a flood, do not walk or wade through a flooded area. Be prepared to evacuate. And if you do evacuate by vehicle, don’t drive where water is over the road. If your car stalls in a flooded area, leave it as soon as possible. Because homeowners insurance doesn’t cover flood damage, consider buying flood insurance for your property.
“The fresh water flooding effects can be very significant from tropical storms, it doesn’t take a major hurricane or a hurricane.”
Just as dangerous as flooding, hurricane force winds can blow over trees, knock down power lines and destroy poorly constructed homes. North Carolina suffered significant wind damage when Hurricane Hugo struck the Outer Banks as a category three storm in 1989. By the time it reached Charlotte and other inland areas, the storm had sustained winds of 69 miles per hour and gust of 87 miles per hour, still strong enough to topple trees across roads and houses.
“The wind effects for trees falling on homes can be extremely dangerous. Many people have lost their lives from trees falling on homes and when we start seeing winds of 70, 80, 90 or 100 miles per hour trees can come down and you’ll start to see significant structural damage.”
After the back to back Hurricanes Fran and Bertha in 1996, people began being proactive about taking trees out of their yards. Prepare your yard for hurricane season by examining trees for any signs of decay and weakness and have them trimmed or removed. To protect windows, homeowners can use plywood to cover exposed glass. A more permanent option includes installing impact resistant windows or storm shutters. In high winds, anything left outside can become a flying object that can cause injury or damage. Put away any outdoor toys, furniture, trash cans, planters or grills.
Since eastern North Carolina is surrounded by large bodies of water, our geography makes us vulnerable to storm surge.
“Surge I think is probably the number one threat to taking lives.”
Storm surge occurs when water is pushed toward the shore by the force of the winds swirling around the storm. In inland areas, storm surge could mean life or death. During Hurricane Isabelle, storm surge caused extensive damage to homes and buildings in the Adams Creek area, where over 10 feet of storm surge from the Neuse River rose quickly, leaving residents barely enough time to evacuate their homes. Fortunately, during that storm, there were no fatalities.
“It doesn’t take a major hurricane to cause really disastrous storm surge, we saw that with Hurricane Isabelle in 2003, we saw it with Hurricane Irene in 2011. My advice would be to listen to the local elected officials if they advise evacuations or if they issue evacuations, then do so without hesitation.”
The National Weather Service and the National Hurricane Center use computer models to gauge the impact of storm surge on a particular area during a hurricane. A team of researchers at the North Carolina Institute of Marine Sciences in Morehead City have spent twenty years developing a computer model for measuring how the ocean moves. And since 2008, they’ve been using the technology to determine the impact from storm surge on an area as a hurricane makes landfall.
“our models then predict how the ocean is going to respond to these events. And, not only the ocean in its normal banks are going to respond to it, but once it overflows the banks and inundates the coastal areas as well as the estuaries and up into some of the lower river systems.”
Rick Luettich is the Director of the University of North Carolina at Chapel Hill’s Center for the Study of Natural Hazards and Disasters. He is also the director of the North Carolina Institute of Marine Sciences. Luettich says being able to measure the movements of the ocean allows them to warn people if they live in a vulnerable area and help them determine safe evacuation routes.
“and then during an actual event, or leading up to an actual event, we can give our best prediction as to how we think the best response is going to occur where the ocean is going to move to and what areas are going to get flooded in the coastal zone.”
The storm surge model, also known as ADCIRC, was used by the Army Corp of Engineers to design and implement a hurricane protection system around New Orleans. It was also used by the National Flood Insurance Program to re-evaluate risk maps. Luettich says the National Hurricane Center uses the ADCIRC model along with other computer models to help develop forecast and issue warnings and alerts. The model results are updated twice a day and can be viewed online at coastalemergency.org.
“they’ll give you information on water level. If there was a storm out there that was going to cause some localized coastal flooding, you can see that. It also gives you information on wave condition. And then, when a major tropical cyclone is coming, we shift over and run four times a day, every time an advisory is released from the National Hurricane Center on the actual specifics of the tropical cyclone itself.”
Whether it’s storm surge models or hurricane warnings and watches, distributing information to the public is top priority during hurricanes or tropical storms. Local elected officials, weather service offices, the media, and County Emergency Management offices all play an integral role in keeping the public safe.