EF3 Tornado — Owen, Indiana

2023-03-31 · near Spencer, Owen, Indiana

Event narrative

The rotating supercell thunderstorm tracked over the town of Spencer before spawning a second, violent EF3 tornado, that first tracked through extreme northeastern Owen County. The tornado touched down in the McCormick's Creek State Park Campground Loop B, where EF2-intensity winds produced extensive tree damage. About 400 yards east the tornado impacted many campers at Campground Loop A, where two campers were killed and two others were injured. About 1.25 miles to the east-northeast further EF2-intensity damage occurred at Concord Road where large sections of a home's roof were removed while cars where crushed, rolled and thrown; here along the circulation's southern side the roof was blown off of a mobile home as it slid off its block piers, yet remained upright, consistent with high-end EF1 intensity winds.

The tornado intensified to EF3 strength as it neared the Owen-Monroe County line, with two barns 300-500 feet west of North County Line Road completely gone as their debris was lofted a quarter mile into Monroe County; a new farm combine weighing about 12 tons and other tractor implements were lofted and thrown 50 yards; debarking of trees also began near County Line Road, with only stubs of largest branches remaining, from the tornado's strongest winds of 153 mph. Less intense damage was again observed south of the path's center near the county line where unanchored outbuildings were destroyed by collapsed walls; and single-family homes experienced minor loss of roofing and broken glass, consistent with EF1-intense winds. The tornado maintained EF3 intensity while crossing into Monroe County.

Wider weather episode

A strong, occluding storm system over the Upper Midwest produced a deep column of strong southwesterly winds over the Midwest on the afternoon and evening of the 31st.

This pattern generated an inordinate amount of vertical wind shear. The overall southwesterly flow also brought rather mild and somewhat humid air into the region, which was adequately unstable given noticeably colder air aloft, especially over the southwestern quadrant of Indiana.

Resulting thunderstorms were able to mix down the stronger winds to the surface as damaging straight line gusts, while a rather low freezing level promoted isolated large hail. Ten tornadoes occurred across the region: 5 from a rotating supercell thunderstorm that tracked roughly parallel to and about 20 miles south of Interstate 70, and 5 others spawned from a squall line's northern book-end vortex that impacted north-central central Indiana. The supercell's first two tornadoes (both EF3) caused a combined 5 fatalities...before the supercell spawned two more strong tornadoes (EF2/EF3), with the cell's final EF3 inflicting major damage on a warehouse in Whiteland (Johnson Co.). The (northern) squall line's first tornado was an EF2 that impacted mostly rural areas...while the squall line's four following tornadoes were all weak (EF0/EF1), with the final three spawned over Howard County, concluding with a longer tracking EF1 that injured one person.

View location on OpenStreetMap → (39.2978, -86.7282)

Source: NOAA Storm Events Database, event_id 1089564. Narrative written by the NWS forecast office that issued the report.