EF0 tornado in Clay County, Iowa

A tornado developed a little less than one mile north of Webb just east of 290th Avenue in an open field. The tornado was documented by numerous individuals as it tracked east-northeast for a little over a minute. The tornado crossed 300th Avenue near a farmstead where trees were damaged along the north side of the property and the resultant winds caused minor damage to the residence. The tornado continued toward the east-northeast for a little over a minute over open fields and lifted just before 310th Avenue south of 470th Street. The tornado was rated EF0 with a maximum estimated wind speed of 75 mph. The average path width was 30 yards.

At late afternoon, considerable moisture focused near a strong warm front from low pressure across northeastern Nebraska through northwest Iowa. Climatologically significant mid-level lapse rates produced a strong capping inversion which gradually weakened north of the warm front. Storms initiated with effective deep-layer shear from 40 to 50 knots and quickly became severe hail producers north of the warm front across southeast South Dakota into southwest Minnesota during the late afternoon, with additional storms developing in proximity to the surface wave across northwest Iowa. One of these latter storms produced two weak tornadoes across northwest Iowa.