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Dr. Jeffrey Masters, Director of Meteorology for the Weather Underground Web site, answered student weather and hurricane questions.

Dr. Masters received his B.S. and M.S. degrees in Meteorology from the University of Michigan. He has taught weather forecasting at the State University of New York Brockport, and joined the Hurricane Hunters as a flight meteorologist for the National Oceanic and Atmospheric Administration's (NOAA) Aircraft Operations Center. You can see him in the 1988 PBS documentary NOVA show "Hurricane!" flying into Hurricane Gilbert.

After four years of flying through the most extraordinary weather on the planet (and nearly getting killed flying into Hurricane Hugo), Jeff left the Hurricane Hunters to pursue a Ph.D. degree in air pollution meteorology from the University of Michigan. Jeff currently lives in Michigan with his wife, Diane, and 3-year old daughter, Ellie. He enjoys hiking, windsurfing, cross-country skiing, and meditation.

Q: Is it hard predicting the weather (hurricanes)? Brandon L., age 10
A: Yes, the average error in position for a three-day forecast is over 300 miles, and forecasters have very little skill in predicting if a hurricane will get stronger or weaker.

This lack of skill is due to two factors:

1. There is very little weather data available in the vicinity of hurricanes, because they occur over oceans where there are very few weather stations making measurements. This situation is improving, though — in the past 2 years, the National Hurricane Center has been using a jet that flies around a hurricane and drops probes that make weather measurements. When data from the probes are analyzed, the forecast of the hurricane's track improves by about 20 percent.

2. Scientists still lack basic understanding about how hurricanes work. There is a determined research effort underway to gather more information about hurricanes and develop improved forecasting models of these complicated phenomena.

Q: Why was Hurricane Andrew so destructive? Andrew S., age 10
A:Hurricane Andrew had very strong winds (145 mph sustained) and hit a heavily populated area.

Q: Does a hurricane always turn in the same direction? Joey, age 11
A: Not always, but usually. Once a hurricane gets north of Florida, it almost always re-curves to the north and northeast.

Q: Can a hurricane destroy the Statue of Liberty? Lisa, age 15
A: New York City has only gotten a direct hit from a major hurricane (winds over 110 mph) only in the past 300 years, so there are not many opportunities for a hurricane to knock down the statue. I doubt that even a major hurricane could knock down the statue, though, it is a pretty tough structure.

Q: How much damage can a hurricane do to a city? Sarah Elizabeth K., age 11
A:The record is $25 billion dollars to south Florida in 1992 during Hurricane Andrew.

Q: How does a hurricane stop? Jamie, age 10
A:If the upper-level winds pushing the hurricane stop blowing, then the hurricane stops.

Q: How do hurricanes get stronger? Ryan, age 12
A: Their energy source is the heat in warm ocean waters. Hurricanes are able to convert this heat energy into the mechanical energy of its winds.

Q: How big are hurricanes? How big can a hurricane really get? Ashley, age 6; Michael, age 7
A:They range in size from 60 miles in diameter to 1,000 miles in diameter. The biggest can be 1,000 miles in diameter.

Q: How do hurricanes get their names? Also, why are they usually female names? Charmaine E., age 11
A:Tropical cyclones are named to provide ease of communication between forecasters and the general public regarding forecasts, watches, and warnings. Since the storms can often last a week or longer and that more than one can be occurring in the same basin at the same time, names can reduce the confusion about which storm is being described. Between 1951 and 1977, hurricanes were given female names. Beginning in 1978, both male and female names began being used, alternating with each letter of the alphabet.

Q: How long can hurricanes last? Anjali, age 11
A:The record is 28 days, for Hurricane Ginger in 1971.

Q: Why does the pressure lower in a hurricane? Lucas, age 10
A:Low pressure at the center is a feature of all large storm systems and results from a complicated interaction between the spin of the earth and the physics of how gases behave in our atmosphere.

Q: What month has the most hurricanes on record? Claire, age 6
A:September. The peak of hurricane season is September 10, with about half of all hurricanes occurring before and half after.

Q: Can a hurricane turn into a tornado? Ryan, age 10
A: No. Hurricanes are vast in scale, sometimes extending more than 1,500 kilometers in diameter. Within the hurricane, smaller tornadoes occur, with diameters of only a few hundred meters. These tornadoes often cause great destruction and loss of life.

Q: How do you know when a hurricane is coming? How bad can hurricanes get? Can hurricanes occur in Michigan? Amber M., age 11
A:Weather satellites tell us when a hurricane is coming. Aircraft go into the storm to tell us how strong it is. Hurricanes can have winds up to 200 miles per hour, rainfall of 20 inches or more, and a flooding "storm surge" that comes ashore with the eye of 25 feet or higher. No hurricane has ever made it to Michigan, although the remnants of Hurricane Hazel in 1954 hit Toronto with devastating flooding that killed many people.

Q: What areas are most likely affected by hurricanes? Wanda, age 15
A:Florida has gotten the most hits of any state in the U.S.

Q: How does a weather balloon work? We have seen pictures in our science book, but we don't know how a balloon can tell the weather. Mrs. B's 5th grade, age 10, New Jersey
A:A one-pound instrument package is attached to the balloon before it is released. This package has a thermometer, barometer, and humidity sensor on it. A radio transmitter sends the data to the ground station as the balloon rises. Winds affecting the balloon can be inferred from how fast the balloon gets blown away from the launch site.

Q: What were the ten deadliest hurricanes of all times? Annimarie, age 13
A: The top ten are:

1. In the Atlantic, the deadliest of all time was the Great Hurricane of 1780 that ravaged Barbados and other Caribbean islands and killed over 22,000 people.
2. Hurricane Mitch, Honduras, 1998, 9,000 killed.
3. Great Galveston Hurricane, 1900, 8,000 killed.
4. Hurricane Fifi, Honduras, 1974, 8,000 killed.
5. Unnamed hurricane, Dominican Republic, 1930, 4,000–8,000 killed.
6. Hurricane Flora, Haiti, Cuba, 1963, 7,000 killed.
7. Pointe-a-Pitre Bay Hurricane, Guatemala, 1776, 6,000 killed.
8. Newfoundland Banks Hurricane, 1775, 4,000 killed.
9. Unnnamed Hurricane, Puerto Rico, Carolinas, 1899, 3,400 killed.
10. Lake Okeechobee Hurricane, Florida, 1928, 3,400 killed.

Q: How do hurricanes occur? Katie, age 10
A:Hurricanes start life as a "tropical disturbance" or "tropical wave" — a cluster of strong thunderstorms moving across the ocean. Atmospheric conditions must be just right to turn a tropical wave into a hurricane; less than 5 percent of all tropical waves make it. To get a hurricane you need:

1. Ocean water temperatures of at least 80° Fahrenheit (to provide lots of heat energy for the storm to feed off of). Thus, hurricanes (in the Northern Hemisphere) form in June–November, when ocean temperatures are at their peak. September 10 is the peak of hurricane season in the Atlantic Ocean.

2. Low wind shear from the top to the bottom of the atmosphere. For example, if the winds at the surface are light and winds at high altitude over the tropical wave are strong, this "shear" will act to tear the developing hurricane apart.

3. Something to get the tropical wave spinning. This is usually provided by a low-pressure system or front that moves from land over the tropical ocean. The part of the spin of the earth that points straight up at the point of interest (the Coriolis force) must help out to get the storm spinning; near the equator, the Coriolis force is zero, so no hurricanes form within about 500 miles of the equator
   
   

Q: What happens before, during, and after a hurricane (winds, pressure, etc.)? Nelmarie L., age 13
A: As a hurricane approaches, the clouds steadily thicken, the pressure begins to fall, and the winds rise. Large, rhythmic waves created far out at sea by the hurricane's strong winds begin to pound the shore. As the hurricane arrives in full force and the eyewall hits land, a dome of water up to 25 feet high called the storm surge moves ashore, frequently causing tremendous devastation. Torrential rains add to the flooding, and the hurricane's mighty winds reach their peak. As the calm eye moves ashore, the lowest pressure is recorded and the winds die down. Once the eye finishes crossing, the winds resume in intensity, and the pressure begins to rise. The winds drop off in intensity as the eyewall departs, and the pressure continues rising as the storm moves off.

Q: If there is a hurricane close to an island, how big are the waves? Nick W., age 10
A:A major hurricane with 150-miles per-hour winds can make waves 30 feet high crash onto nearby islands. Out at sea, waves over 100 feet high have been measured by ships.

Q: How long does a hurricane usually last? Joey B., age 9
A:Usually hurricanes last about a week. This year's Hurricane Alberto was the third-longest-lived Atlantic hurricane on record; it lasted 20 days from the time it formed as a tropical depression on August 4.

Q: In our study of weather, we learned about the greenhouse effect. One thing that we learned was that some heat escapes into space during the process. Why? Mrs. Berk's 4th-grade class, age 9
A:Everything that is warmed by the sun, including the ground and the molecules of gas in the atmosphere, gives off heat that radiates in all directions. Some of this radiated heat goes up towards space, and unless there are clouds in the way to block it, the heat escapes into space.

Q: Hello, my 3rd-grade class is studying hurricanes, and we are currently doing research on the good things that a hurricane can do for us, the air, etc. We have found only three things:
1) They balance the earth's temperature;
2) They bring water to dry places; and
3) Hurricanes clean the air.
Are there any other good things that you know of? Mrs. Macke's 3rd-grade class, age 9
A:That pretty much covers it. Hurricanes have been very beneficial in stopping long droughts in some areas, and they make up an important contribution to the long-term rainfall in areas like the Southeastern U.S. In more human terms, I like to think that hurricanes offer us a chance to reflect on our place in nature. The awesome destructive power of a hurricane reminds us to be humble and realize our powers are insignificant compared with the powers of nature, and that we should learn to try to coexist with nature instead of trying to subdue it.