Story County tornado was more than 1,000 yards wide, first touched down near Johnston

Tuesday's Story County tornado traveled 41 miles before expiring near Zearing, the National Weather Service determined, earning an EF-2 rating.

The twister first touched down around 4:30 p.m. May 21 near Johnston carving a path more than 1,000 yards wide featuring peak wind gusts of 135 miles per hour.

Story County Emergency Management announced late Wednesday that two individuals sustained non-life-threatening injuries.

The rotation eventually expired around 5:05 p.m. the National Weather Service said, lasting more than half an hour, generating damage in Cambridge and Nevada. The damage in Johnston included the local high school, which canceled classes on Wednesday.

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Tornado leaves elongated damage path

Story County officials said the tornado traveled along the eastern edge of the county Tuesday evening, knocking down power lines, damaging houses, and scattering debris throughout the area.

Iowa Department of Transportation cameras also captured the tornado crossing U.S. Highway 30 near Nevada. The camera showed a stop semitrailer being pushed over as the tornado and debris moved across the road shortly before 5 p.m. on Tuesday.

The semi driver did not report any injuries, Iowa State Patrol Sgt. Alex Dinkla told the Des Moines Register on Wednesday.

The EF-2 rating is according to the Enhanced Fujita scale, which rates tornado intensity on a scale of zero to five based on the damage they cause. An EF-2 is capable of tearing roofs off well-constructed houses, lifting cars off the ground and uprooting trees.

More: A tornado knocked down power lines and devastated homes in Story County Tuesday night

Story County continues assessing damage, signs disaster proclamation

Story County Damage Assessment Teams are performing residential damage assessments that were expected to be completed Thursday afternoon.

Story County Emergency Management is working with partners throughout the county to restore utilities to impacted communities.

Colo was the only community completely without power following the tornado. Crews from Alliant and Consumers Energy Cooperative are repairing downed power lines throughout the county and are optimistic that Colo will be fully restored on Thursday.

The Story County Emergency Management Commission has also signed a countywide local disaster proclamation.

The local declaration assists with the State of Iowa’s Individual Assistance program, which is available to residents who meet the program requirements.

Severe weather may be possible heading into Memorial Day weekend

Additional severe weather is possible late Thursday heading into the Memorial Day weekend in sections of the state.

According to the National Weather Service, thunderstorm chances return late Thursday likely through the overnight hours. A marginal risk of severe weather is possible in western Iowa, with hail and gusty winds the primary concerns.

On Friday, thunderstorms may develop during the day, which the National Weather Service says will clear out by the evening. A marginal risk of severe weather is possible in eastern Iowa during the afternoon and evening.

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Celia Brocker is a government, crime, political and education reporter for the Ames Tribune. She can be reached at CBrocker@gannett.com.

This article originally appeared on Ames Tribune: Story County tornado classified as EF-2, traveled 41 miles