Hail and Damaging Wind in Iowa, August 5, 2000

A very unstable airmass was in place over Iowa as surface dew points climbed into the mid 70s to low 80s. CAPE values were near 8000 J/kg by the late afternoon hours. The airmass was capped with 700 mb temperatures between 15 and 17 degrees C. A weak upper level system moved into the state in conjunction with a surface trough of low pressure. An existing outflow boundary extended from near Omaha to just south of Des Moines to Ottumwa. At the triple point, thunderstorms erupted over western Iowa. The storms became severe very quickly and produced large hail. The environment was a very sheered one. Hail of two to three inches in diameter fell in Cass and Adair Counties with this storm. The event was mainly centered around one supercell. The hail caused damage to roofs and cars. Crop damage was extensive as the near mature crop was beat to the ground in places. The storms did produce gusty winds, but the only report of damage came from the Marne area of Cass County where 60 to 70 MPH winds were reported by the Emergency Manager.