EF1 tornado in St. Helena Parish, Louisiana

An EF-1 tornado quickly spun up along a line of strong thunderstorms near Liverpool LA, south of LA 1043. This tornado caused predominantly uprooted and snapped tree damage as it tracked southeast. It began to track more east-southeast as it exited St Helena Parish and entered Tangipahoa Parish near LA 10 just west of I-55. Peak intensity was 95 mph and max width was 200 yards.

Environmental conditions favorable for a QLCS (Quasi-Linear Convective System) tornado event developed across southeast Louisiana and southern Mississippi during the afternoon and evening hours of March 11th. An upper-level storm system moving east from Texas overspread a very moist and increasingly unstable air mass in place across the region. At the same time, intense low-level wind shear and strong atmospheric spin developed as southerly winds strengthened ahead of an approaching line of storms with bowing segments.

The combination of rich Gulf moisture, strong low-level atmospheric spin, and a fast-moving line of thunderstorms created an environment supportive of embedded rotating circulations along the leading edge of the QLCS. As that line moved west to east across the local area, several rapidly developing tornadoes formed within these circulations. A total of 8 tornadoes were confirmed across southeast Louisiana, including 2 with path lengths exceeding 10 miles. Well over a dozen additional reports of damaging straight-line winds were also received.