Hail and Damaging Wind in Iowa, April 12, 1998

The intense low pressure system mentioned above also produced widely scattered severe weather. In spite of very strong dynamics, severe weather was quite spotty. Moisture was very limited with surface dew point temperatures in the upper 40s to low 50s F. over the area. A dryline extended south from the low. Thunderstorms fired along this dryline. A small bow echo formed over northwest Iowa. High winds were reported just west of the Des Moines area of responsibility with 78 MPH winds reported in Dickinson County at Spirit Lake. Gust winds moved eastward with the bow echo, however winds remained below severe criteria in most areas. High winds did sweep through southern Sac County as one farm south of Odeboldt was hard hit. Winds of around 75 MPH toppled 3 grain bins, a garage, and several out buildings. Two vehicles were destroyed as the garage blew down. A cold pool aloft moved over Iowa during the early evening hours with 500 mb temperatures around -18 C. This produced very steep lapse rates over Iowa. Meanwhile, the freezing level was only 9900 ft MSL, producing a favourable profile for hail. Hail was then the main weather event through the rest of the evening. The storms that did produce severe weather were hail producers with three quarter to one inch diameter hail being reported from the cells. There was several reports of pea to marble size hail covering the ground over northwest Iowa as well. The line produced hail over Crawford and Carroll Counties before weakening somewhat. They briefly flared up again over Worth County and dropped nickel size hail there.