Lynn Chandler
Goddard Space Flight Center, Greenbelt, Md.
(Phone: 301-614-5562)

September 6, 2000
RELEASE: 00-109

HURRICANE FORECASTS MORE ACCURATE ON 100th ANNIVERSARY OF DEADLY GALVESTON STORM

As the 2000 hurricane season reaches its midpoint this weekend, meteorologists are much better prepared to forecast dangerous storms like the hurricane that slammed into Galveston Island, Texas 100 years ago.

"Scientists have many more valuable tools to work with than were available in 1900," said Marshall Shepherd, outreach scientist on NASA's Tropical Rainfall Measuring Mission (TRMM) project at NASA's Goddard Space Flight Center, Greenbelt, Md. Scientists now use computer forecast models, weather satellites that track storms and remote-sensing satellites like TRMM that see through upper level clouds to find the eye of a storm and track rainfall and ocean temperatures.

"On September 8, 1900, however, the 38,000 residents of Galveston Island had none of these tools, awaking to storm surges from what is now known as 'The Great Galveston Hurricane,'" Shepherd said.

"The storm came off the Florida Keys as a tropical storm, intensifying to a category 4 hurricane as it tracked through the north Caribbean," said Bill Read, Meteorologist-in-Charge at the Houston-Galveston National Weather Service Office, one of the ground validation sites for TRMM radar data.

According to the National Hurricane Center (NHC), which forecasts, tracks and records information about hurricanes, the storm is tied for the seventh most intense U.S. hurricane with a minimum central pressure of 931 millibars, or 27.49" of mercury. By mid-afternoon on Sept. 8, high water forced in from the hurricane had washed out the four bridges to the mainland, downed telephone lines and flooded the entire island, cutting Galveston off from the mainland.

High winds and storm surge destroyed thousands of homes. Estimated damages in 1996 dollars were $1.3 billion, making the storm one of the 30 most costly hurricanes in history, according to the NHC. Although the official death toll stands at 8,000, some estimates go as high 12,000, including fatalities on the Texas mainland. "The Galveston Hurricane was so devastating that the '1900 Storm Commemoration Committee' was formed in 1998 to commemorate the storm's 100th anniversary, to educate the public about the storm and to celebrate the subsequent rebirth of the community," committee chairman Mike Doherty said. For more information about this historic event and celebration, go to: http://www.1900storm.com/

To prevent such tragedy from occurring again, a sea wall was completed in 1904. The wall still stands today 17 feet above mean low tide and runs three miles along the portion of Galveston Island that faces the Gulf of Mexico and drops downward to the back of the island. Today, if residents don't evacuate 35-50 hours before 39 mph sustained winds reach Galveston they won't get off the island.

The NHC uses the Geostationary Operational Environmental Satellite (GOES) to monitor and track tropical cyclones and also relies on data from TRMM. Although TRMM's mission focuses on the tropics, it can see beyond from 35 degrees north latitude to 35 degrees south latitude. The many benefits of rainfall data include improved hurricane tracking and rainfall accumulations produced by computer prediction models, and proven in the forecasts of 1999's Hurricanes Dennis and Floyd.

Robert Molleda, a meteorologist with the Tropical Prediction Center in Miami, said the National Hurricane Center currently uses TRMM data in addition to data from conventional weather satellites, especially when mid- or upper-level clouds prevent hurricane specialists from finding the center of a storm. "TRMM data helps find the center of circulation of tropical cyclones when they are obscured by these clouds, or when the center of circulation is poorly defined because it is a relatively dry area," Molleda said.

One instrument aboard TRMM, the Microwave Imager (MI), is capable of measuring sea-surface temperatures through clouds. Science team members say that data from the MI sensor has great potential to increase the accuracy of tropical storm and climate forecasts. "Because TRMM's microwave radiation penetrates clouds with little loss of signal, scientists are provided with an uninterrupted view of sea surface temperatures, which is a critical component in forecast models for determining whether a tropical storm or hurricane will gain or lose strength," Shepherd said. "TRMM carries the first space-borne rain radar, which has provided dramatic views of intense thunderstorms in the eyewall of past Hurricanes Bonnie and Floyd, among others."

With data from TRMM, hurricane forecasts and tracks are likely to continually improve, leading to better preparation for hurricanes and a reduction in unnecessary evacuations during hurricane season. TRMM is a joint U.S.-Japanese mission and part of NASA's Earth Science Enterprise, a long-term research program designed to study the Earth's land, oceans, air, ice and life as a total system. Information and images are available at: http://trmm.gsfc.nasa.gov/ Additional information about hurricanes and tropical storms is available on the NHC website at: http://www.nhc.noaa.gov/

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