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Western South Dakota Tornadoes
On June 23, 1998, tornadoes touched down in Meade County, just north of Rapid City. This photo was taken from the National Weather Service Rapid City office by Molly Zeitler. At ground contact the tornado was estimated to be a quarter mile wide.
Tornadoes are not uncommon in South Dakota, but they are a rarity in the immediate vicinity of the Black
Hills. For the period 1950-1994 the state ranked 8th in the number of confirmed tornadoes, but the vast
majority of these were in the central and eastern portions of the state.
The only tornado touchdown ever recorded in the Rapid City limits took place on Father's Day in 1967 when
a small twister briefly made ground contact on Mount Rushmore Road near the Town & Country Inn. It then
skipped along to the northeast through Robbinsdale with damage reported at the motel and to a few nearby
homes. There is no record of anyone ever being killed by a tornado in Rapid City.
There have, however, been some close calls, for Rapid City. One tornado touched the ground northeast of
Sheridan Lake on the afternoon of July 23, 1966 and left a trail of destruction southeastward to just west
of Rockerville. On June 23, 1998 tornadoes touched down in Meade County east of I-90 between Piedmont and
Tilford. As many as four funnels took turns moving slowly east over a three hour period from 6 to 9 PM.
A wall cloud east of Black Hawk that spawned one of the Meade County
tornadoes on June 23, 1998 as seen by KEVN's Powercam.
This view of the June 23, 1998 Meade County twister was taken from
news crew footage shot by a KEVN/Fox7 News photographer
Until recently, an average tornado season might produce two or three tornadoes within a hundred twenty mile
radius of Rapid City. Nearly all of these would usually be classified F0 or F1 storms, meaning they trended
toward the smaller, weaker and briefest of the tornado family. In the past few years, however, the National
Weather Service in Rapid City has been issuing more tornado warnings. The reason or reasons for this are
the subject of ongoing study.
One theory behind the increase is the greater influx of people to the Black Hills results in a greater
likelihood of a tornado being seen and reported. Another school of thought is that North America is
undergoing a cyclical climate modification which has caused an increase in the number of tornado producing
storms in western South Dakota. Still another opinion is that technological advances, such as the
installation of Doppler radar and improved storm spotter training have resulted in the increase, and there
may be something to this.
Doppler radar is able to "see" into a storm and detect the motion of the winds within the thunderstorm
clouds. The unit scans for small areas of the storm where winds are blowing toward and away from the radar
antenna at the same time in close proximity. The radar then can scan up and down in the storm to determine
if the area of rotating air extends vertically for any distance in the parent cloud. If it does, and the
Doppler measured wind speeds are high enough, this area is designated as a "tornado vortex signature" or
TVS. The TVS shows up on the Doppler display as two contrasting areas of color close together. At the right
is the display from the National Weather Service Doppler radar near New Underwood on June 23, 1998 with the
TVS circled in the center.
Of course, there is nothing to say that the three theories on the increase in western South Dakota tornado
warnings are exclusive. It is plausible, perhaps even likely, that elements of all three theories have
contributed to the increase. The important thing is that tornado detection is improving, and that warnings
are getting out to the public as a result.
This graphic is a plot of every confirmed tornado touchdown and tornado paths in the Black Hills region
between January 1, 1955 and December 31, 1995. It was prepared by National Weather Service meteorologist
Brian Klimowski for Dan Carlson. The pink triangles are touchdown points, and the lines are the paths taken
by tornadoes on the ground. The absence of lines in relation to triangles indicates that the majority of
the region's tornadoes do not remain on the ground long.
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