Thunderstorm Wind — Fountain, Indiana

2021-10-11 · near Attica, Fountain, Indiana

Event narrative

Significant tree damage across the town of Attica due to strong straight line winds associated with a bookend vortex. 3 houses had damage from trees falling on them with one minor injury in one of the residences. Near the golf course on the south side of the town, a free standing radio antenna was bent over with a noticeable amount of rust at the base. Elsewhere, the high school lost a portion of the roof which led to water damage in the school.

Wider weather episode

The gradient between a ridge over the Appalachians and a trough just west of the region, quickly ejecting to the north-northeast...resulted in a robust low level jet (LLJ) of 45-60 mph at the 850 mb level. Strong wind shear between the LLJ and southerly surface flow of about 15 mph combined with modest yet adequate instability, to produce multiple lines of thunderstorms from the late afternoon into the evening. The strongest embedded cells brought the LLJ's winds, as well as isolated large hail to the surface over northwestern central Indiana. An initial line of thunderstorms produced the majority of the damage with a bookend vortex causing the most intense damage within Attica. A brief and stronger updraft caused 1 inch hail to fall in Montgomery county. Later, a convective line of showers with weak rotation caused additional tree damage in Clinton and Carroll counties.

View location on OpenStreetMap → (40.2900, -87.2500)

Source: NOAA Storm Events Database, event_id 979049. Narrative written by the NWS forecast office that issued the report.