May 1, 2006 Three severe hurricanes hit the U.S. in 2005. Weather forecasters now hope to reduce the loss of lives caused by hurricanes with better computer modeling. With more precise predictions of a storm's path and strength, scientists can give advance evacuation advisories.
In 2005 three very serious hurricanes hit the United States, leaving 1,300 Americans dead and millions homeless. Researchers just announced that we're in store for another rough storm season. But using new tools, meteorologists can now tell how many storms will occur and how bad they will be.
Deadly winds and powerful storm surges ... Knowing when and where intense hurricanes will make landfall can mean the difference between life and death. Survivors of Katrina, the most destructive hurricane to hit the United States, know firsthand just what these storms can do. And before we can fully recover from the storms of 2005, the 2006 hurricane season is just about to begin.
Hurricane season kicks up in June and lasts through November. Right now, researchers at the National Oceanic and Atmospheric Administration, also know as NOAA, are trying to figure out what's going to happen in 2006.
"We need to better predict the track, where the storms are going to go, the intensity -- or how strong the winds -- and size of the storm, the rainfall, and the storm surge," Chris Landsea, the Science and Operations Officer at NOAA's National Hurricane Center in Miami, Fla., tells DBIS.
He says there are three key factors in predicting hurricanes. "We look at the temperatures of the Caribbean and the Gulf of Mexico in the Atlantic. We look at the wind shear over the ocean, or the changing winds with height."
While a wind shear -- or any change in wind speed or direction over a short distance -- may make unstable skies ripe for storm development, the best indicator is how warm the gulf waters are.
Hugh Willoughby, an atmospheric scientist and meteorologist at the International Hurricane Research Center at Florida International University in Miami, says, "The water is somewhat warmer than usual, but not nearly as much as it was last year. Which kinda leads us to think it's going to be an active season, but not like 2005."
And whether we're in an El Niño or La Niña will also impact the number of storms and their strength.
"One nice thing about El Niño," Landsea says, "is it causes a disruption of hurricanes."
During an El Niño, the wind shear can slice through the top off a hurricane, poking holes in the storm's power. But that's not what's happening right now.
"In fact, there's the opposite -- cooler than normal waters near Ecuador and Peru called La Niña, and it actually makes for less wind shear. So if that sticks around through the height of the hurricane season, that might enhance the season and make it worse," Landsea says.
He says this season the next generation of hurricane modeling will run for the first time. It can simulate a hurricane in the computer. "We get such a good look at what's going on that it should be able to give, not only a better track forecast, but a better idea of what are the worst winds in the hurricane, what's the size of the storm."
And that may be the key to saving more lives.
"Accurate prediction does keep people from dying, but we can't move their houses out of the way," Willoughby adds ... And after last year, nobody should take their safety for granted.
Landsea believes we are in a cycle of rough hurricane seasons. The cycle runs 25 years to 40 years, and we are about 10 years into it ... So he says we could be seeing more storms like Katrina, Charlie and Wilma for the next few decades.
BACKGROUND: New technology is helping scientists with the National Center for Atmospheric Research better detect weather patterns and make predictions. This includes new mobile Doppler radar; radio-controlled aircraft carrying weather instruments in and around storms; phased array radar; and new real-time computer modeling programs for atmospheric conditions.
WHAT IS DOPPLER RADAR: During the 1980s and early 1990s, the National Weather Service installed Doppler radars around the U.S. All weather radars send out radio waves from an antenna. Objects in the air, such as raindrops, snow crystals, hailstones or even insects and dust, scatter or reflect some of the radio waves back to the antenna. All weather radars, including Doppler, electronically convert the reflected radio waves into pictures showing the location and intensity of precipitation. Doppler radars also measure the frequency change in returning radio waves. Waves reflected by something moving away from the antenna change to a lower frequency, while waves from an object moving toward the antenna change to a higher frequency. The computer that's a part of a Doppler radar uses the frequency changes to show directions and speeds of the winds blowing around the raindrops, insects and other objects that reflected the radio waves.
PHASED ARRAY RADAR: Adapted from the SPY-1 radar technology used by the U.S. Navy to spot severe weather while ships are at sea, phased array radar uses multiple beams and frequencies to reduce scan time to less than one minute, enabling faster updates on weather conditions. This technology may help forecasters in the future provide earlier warnings for severe and hazardous weather; for example, it could increase the average lead time for tornado warnings beyond the current average of 11 minutes.
The American Meteorological Society contributed to the information contained in the video portion of this report.