EF1 tornado in St. Charles Parish, Louisiana

Tornado June 20, 2023 · St. Charles Parish, Louisiana

EF1

Rating

3.6 mi

Path length

400 yd

Path width

EF0EF1EF2EF3EF4EF5Unrated

The path drawn at its surveyed width of 400 yards (0.23 mi) — zoom in and the swath grows to true scale. Other tornadoes recorded nearby that day are shown faint.

What EF1 means. On the Enhanced Fujita scale, EF1 is moderate damage: roofs badly stripped, mobile homes pushed off foundations or overturned, windows broken, consistent with estimated gusts of 86–110 mph. The rating comes from a survey of the worst damage after the storm, not from a wind measurement, so it says as much about what the tornado hit as about how strong it was.

What the National Weather Service wrote

A thunderstorm developed a vigorous mesovortex along a boundary over Lake Salvador just before 2100 UTC. This mesovortex intensified and tracked northwest into the Salvador Wildlife Management Area where a large tornado damage path was visible on high resolution satellite imagery. Widespread tree damage including swaths of uproots and snaps of softwood trees as well as ground scouring and rowing marks from the parent mesovortex were observed indicative of a significant tornado. KLIX radar imagery supports this approximate 4 mile track inland with a 40 knot rotational velocity and weak tornado debris signature evident to at least 4000 feet where the most severe damage was located midway along the path. Thereafter, the tornado path gradually narrowed and weakened and its estimated the tornado dissipated around 21:07 UTC. A ground survey was later performed to assess the highest end damage from this tornado which confirmed the existence of several snapped bald cypress trees.

The wider storm

A northwest upper level flow regime was in place. This setup commonly supports summertime severe thunderstorms. This event was one of those days where very steep lapse rates and high shear values supported several severe thunderstorms with damaging wind and large hail.

Began near Boutte (29.7600, -90.2800).

Source: NOAA Storm Events Database, event 1170546. Narratives are written by the National Weather Service forecast office that issued the report.

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