EF1 Tornado — Allendale, South Carolina

2022-04-05 · near Ulmers, Allendale, South Carolina

Event narrative

A National Weather Service Storm Survey Team confirmed an EF-1 tornado with an estimated maximum wind speed of 95 MPH in Allendale County, South Carolina, which eventually tracked northeast for nearly 35 miles, becoming a strong EF-3 tornado with an estimated maximum wind speed of 160 mph across Bamberg County, South Carolina before dissipating in Orangeburg County, South Carolina (see Storm Data from Columbia, South Carolina for Bamberg and Orangeburg Counties).

The long-track tornado initially developed in Allendale County, approximately 1/3 mile north of Highway 301 across a farm just west of Well Branch Road around 503 PM. Near this location, the tornado threw a grain silo and flipped and threw a few farm trailers and vehicles, consistent with an EF-1 tornado rating. The tornado continued northeast across Wells Branch Road, where it widened to approximately 465 yards and downed many trees before crossing into Bamberg County near the intersection of Highway 321 and Highway 301 at 506 PM.

Wider weather episode

A severe quasi-linear convective system (QLCS) moved through southeast South Carolina during the afternoon into early evening hours of April 5, 2022 as a mid-level shortwave ejected rapidly across the region in advance of a surface cold front. The environment ahead of the QLCS was favorable for severe local storms as southerly winds spread mid 60 dewpoint temperatures into a warm sector across the Southeast United States and favorable mid-level lapse rates and lifted index values helped produce mixed layer convective available potential energy (MLCAPE) as high as 1500-2000 J/kg during peak surface heating across southeast South Carolina. Within the warm sector, strong shear associated with 50-70 knot low and mid-level jets beneath the left front quadrant of a 120 knot upper-level jet, 0-6 km bulk shear around 50 knots, and 0-3 km storm relative helicity in excess of 300 m2/s2 were supportive of well organized convection and potentially embedded supercell thunderstorms in a QLCS capable of producing a prolonged path of damaging winds and strong long-track tornadoes. As the QLCS swept through southeast South Carolina, a few discrete supercell thunderstorms became exceptionally strong near or just ahead of the main line of thunderstorms, producing damaging winds, moderate size hail, and strong tornadoes.

A total of 5 confirmed tornadoes occurred across southeast South Carolina in the Charleston County Warning Area, including two long track EF-3 tornadoes, one which developed in Allendale County southwest of Allendale, SC and ended near Sycamore, SC with an approximately 13.3 mile path, and a second tornado which began in Allendale County near Ulmar, SC, then crossed into the Columbia County Warning Area in Bamberg County at peak strength, before continuing and ending in Orangeburg County with an approximately 34.8 mile path. The South Carolina Forestry Commission estimated 3,389 forest acres damaged by strong winds and tornadoes in Allendale County alone during the severe weather outbreak.

View location on OpenStreetMap → (33.0993, -81.2180)

Source: NOAA Storm Events Database, event_id 1014514. Narrative written by the NWS forecast office that issued the report.