1. By: Pam Avilez & Shelby Frazer ("Highway 72 Microburst - September 28, 2006")

2. A microburst is a sudden, powerful, localized air current. It’s smaller than a macroburst but deadlier! Microburst’s effect areas less than 3km, but can have winds exceeding 250 km/h. Luckily, these only last fewer than 10 minutes on average. It’s small size makes it very difficult to predict and detect. Also, Microburst’s can be as destructive as a tornado! ("Microburst")

3. A microburst has a downdraft that hits the ground and spreads out with a burst of wind. The strong downdraft causing the microburst is formed by cooling. The cooling is cause by evaporation in a cloud. Once the strong downdraft has formed, it is trying to push the cool air out of the downdraft to create a balance with the warm temps of the surrounding air. into A microburst produces “straight-line winds.” These winds can be greater then 104mph to as much as 168 mph. the wind speeds can be equal to the winds of a tornado. The difference between a microburst is that the wind from a microburst is pushed out of the storm, wind from a tornado flows into the storm. (Pearce 1)

4. ("Physical processes of dry and wet microburst's")

5. When rain falls below a cloud base or is mixed with dry air, it evaporates. This evaporation cools the air. The cool air descends and accelerates as it approaches the ground. When the cool air approaches the ground, it spreads out in all directions. The difference in the wind is the signature of the microburst. Dry microburst's, produced by high based thunderstorms that generate not much rainfall. A dry Microburst must include three important items:  Mid-level moisture.  A deep and dry drop rate in the sub-cloud layer  Low surface relative humidity (Razor 1) ("Dry Microburst")

6. Wet microburst’s are downburst’s with major precipitation at the surface. These downburst’s rely more on the drag of the precipitation for downward acceleration. As a result, higher mixing ratios are necessary for these burst’s to form. Melting of ice, usually hail, appears to be important in the downburst formation. These factors make forecasting wet microburst’s very difficult. (Razor 1) ("Wet Microburst") ("Hail Storms")

7. Microburst’s are dangerous to aircraft at low levels, especially on take- off or landing. An aircraft coming at a downburst will first experience a strong wind, which will lead to an increase in air speed. When trying to fly a set airspeed, a pilot might be tempted to reduce power. This would be very dangerous because as an aircraft passes through a downburst, wind becomes a tailwind. The airspeed and lift will drop. The downward force of a microburst may be enough force to bring the aircraft to the ground. (Sky 1) ("Microburst from Plane") ("Crash from Microburst")

8. A derecho is a widespread tornado event which causes new thunderstorms along an overflow boundary. The boundary helps produce more thunderstorms. Occur mostly in the summer months. Derecho’s are usually in northern plain states. The winds from Derecho's can last a long time and cover large areas. Since Derecho's are common in the warm season, people involved in outdoor activity are most at risk. Campers or hikers in forested areas are most likely to be injured or killed by falling trees. People in boats risk injury or drowning, high winds and high waves can overturn boats. People in cars and trucks can be hit by falling trees and utility poles. Also, Semi-trucks can be blow over and crush other cars. (Corfidi 1) ("Rare ‘derecho’ leaves swath of damage across Iowa ") ("Damage from Derecho")

9. ADD VIDEO!

10. If you are in an airplane you have to use full throttle IMMDEDIATLY and climb altitude. You may have to fly on the edge of the microburst. If you are in a jet, you should pitch up to the point of a stick- shaker activation to escape. It’s best to think of this maneuver as an escape maneuver so you don’t confuse it with a normal go-around. You must be calm during this process. (Pendleton 1)

11. DO get a accurate weather report, especially if there could be convective activity. DO watch temp. and dew point spread. Microburst’s are more common with large temp. and dew points spreads. DO maintain visual conditions any time thunderstorms are in the area. DO perform an escape maneuver at any time you think there might be a microburst. DON’T fly under ANY thunderstorm for any reason! DON’T fly under the overhang of any thunderstorm. DON’T fly into or near a rain shaft. DON’T fly under Virga ( built in microburst.) DON’T stand outside. (Pendleton 1)