Heavy Rain and Flash Flooding in the West; Heat Expands in the Central U.S.

Monsoonal moisture will produce showers and thunderstorms with heavy rain over parts of the Southwest, Great Basin, and Central Rockies through Monday. Flash flooding is possible, especially in and around burn scars and in areas of steep terrain. Heat will persist across the Central U.S. early this week, spreading into the Ohio Valley and Mid-Atlantic later this week. Read More >

Overview

Two tornadoes touched down in Ziebach County, South Dakota Tuesday evening, May 12. Scott Olson of Brookings, South Dakota witnessed the first tornado west of Red Elm (see image to the right). National Weather Service meteorologists confirmed a second tornado occurred after conducting a damage survey the following day.

Based on observed damage, the second tornado touched down about five miles west of Dupree and traveled eight miles, with damage ending about three miles northeast of Dupree. Damage included several barns and grain bins, semi-trailers, small mobile homes, and a toppled communications tower. Based on the type of damage, winds were estimated between 100 and 110 mph, giving the second tornado a rating of EF1 on a scale of EF0 to EF5 of the Enhanced Fujita Scale.

First tornado west of Red Elm around 528 pm MDT. No damage was reported with this tornado.
Photo by Scott Olson

Tornadoes
Photos
Radar

Tornadoes:

Tornado - 7.5 miles west of Red Elm, SD
Ziebach County

Date	05/12/2009
Time (Local)	5:28 pm
EF Rating	EF0
Est. Peak Winds	65-85 MPH
Path Length	0.05 miles
Max Width	20 yards
Injuries/Deaths	0

Track Map

Tornado - 2.3 miles northeast of Dupree, SD
Ziebach County

Date	05/12/2009
Time (Local)	5:40 pm
EF Rating	EF1
Est. Peak Winds	100-110 MPH
Path Length	8.23 miles
Max Width	200 yards
Injuries/Deaths	0
Summary: Map of tornado track.

Track Map

The Enhanced Fujita (EF) Scale classifies tornadoes into the following categories:

EF0 Weak 65-85 mph	EF1 Moderate 86-110 mph	EF2 Significant 111-135 mph	EF3 Severe 136-165 mph	EF4 Extreme 166-200 mph	EF5 Catastrophic 200+ mph