Fifteen years ago today, the town of Spencer, SD was devastated by a tornado packing winds in excess of 200 mph. Based upon the devastation and measurements from the Doppler on Wheels radar, the tornado was later categorized as a F4 (on the Fujita scale) tornado by local NWS Sioux Falls' meteorologists and NWS Service Assessment Team members. Even though the town has since rebuilt, many residents still are affected by the memories of that night in May of 1998. The Spencer tornado is now the standard from which all other tornadoes that have since occurred in the area are measured or compared too.
The following paragraph is the opening statement that was made in the Department of Commerce's Service Assessment of the Spencer tornado.
"At approximately 8:40 p.m. (all times Central Daylight Time [CDT]) on Saturday, May 30, 1998, a violent tornado struck the small town of Spencer, South Dakota. Spencer is in extreme western McCook County, about 45 miles west-northwest of Sioux Falls. The tornado killed six people, injured more than one-third of the town's 320 residents, and destroyed most of the town's 190 buildings. Damage is estimated at $18 million. The Spencer tornado (rated F4 on the Fujita Tornado Intensity Scale), was one of five tornadoes, along a nearly continuous damage track approximately 30 miles long."
Below is the map of the tracks of all the tornadoes that occured with the thunderstorm that eventually spawned the tornado that hit Spencer, SD. Notice the tornado reached it's maximum intensity, F4, in and around the town of Spencer. As the tornado aproached Interstate 90, it was weakening dramatically and actually lifted before crossing the Interstate. But shortly after crossing I-90, another tornado was produced by the cyclic supercell and resulted in small stretch of F2 damage northwest of Canistota, SD.
For more information, including photos of the tornado and resultant damage, concerning the Spencer tornado click here. If you have any questions or would like to do an interview concerning this event, please contact Warning Coordination Meteorologist, Todd Heitkamp.