EF1 tornado in Pennington County, South Dakota

Tornado August 11, 2013 · Pennington County, South Dakota

EF1

Rating

1.3 mi

Path length

30 yd

Path width

$25K

Damage as recorded

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The path drawn at its surveyed width of 30 yards (0.02 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 small tornado touched down south of Hill City near the Mickelson Trail. It continued to the south, crossing the Needles Highway (SD Highway 87) east of US Highway 16/385. The tornado blew down and snapped numerous large Ponderosa Pine trees and blew a few shingles off a house. The trees fell onto power lines, which caused the poles to fall.

The wider storm

A severe thunderstorm developed over the central Black Hills and slowly moved south through the southern Black Hills. The storm produced large hail from Silver City to near Hot Springs and a small tornado south of Hill City, which downed many trees and produced minor damage.

Began near Hill City (43.9041, -103.5907).

Source: NOAA Storm Events Database, event 475901. Narratives are written by the National Weather Service forecast office that issued the report.

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