The month of May brought two major severe weather events to South Dakota to include over 20 tornadoes. The first event was the derecho that caused widespread damage to the southeast and the northeast regions of South Dakota. The line of thunderstorms moved into the northeast, South Dakota, several tornadoes dropped from the sky.
The most famous tornado on May 12th, was the EF2 that went through the small town of Castlewood. Several structures sustained significant damage to include the school as the tornado went through town. The peak winds with the tornado were 120mph and traveled on the ground for just under two miles.
Photo Credit: National Weather Service - Castlewood, SD
Into Deuel County, an additional EF2 dropped south of the town of Gary causing significant damage to a farm place and home. The winds within the tornado reached 135mph as the tornado only stayed on the ground for less than a half-mile. A second tornado, an EF1 dropped about two miles northwest of town snapping trees and damaging a house, a garage, and a vehicle.
Down in the southwest part of Deuel County, a large dairy operator was impacted by an EF2 with peak winds of 111mph as the twister tipped over a camper and damaged several outbuildings. This tornado only traveled less than a half-mile as well.
Photo Credit: National Weather Service - 3 miles east of Estelline, SD
One person was injured from an EF1 tornado that came down over a farm about four miles southwest of Thomas in Hamlin County. Maximum winds of 95mph were reported as the 20-yard wide tornado ripped off a roof of a newly built machine shed and damaged exterior walls.
Photo Credit: Hamlin County Emergency Management - 4 miles southwest of Thomas, SD
Other tornadoes during the derecho was an EF1 with peak winds of 110mph about six miles northwest of Rauville. The tornado removed a garage and part of the home's roof. About one mile east of Tunerville a twister damaged a hunting lodge and uprooted several trees. This EF1 tornado was on the ground for just a quarter of a mile and had peak winds of 100mph.
Up towards Webster in Day County, a quick hit tornado with max winds of 100mph dropped about seven miles south of town. The tornado hit an outbuilding and spread debris for several yards.
Photo Credit: National Weather Service - 7 miles south of Webster, SD
Near the town of Garden City, an EF1 with winds of 97mph destroyed a barn roof and damaged external walls to two-thirds of the building. This EF1 was on the ground for just a half-mile. A smaller tornado hit about four miles northwest of Naples with peak winds of 80mph. The tornado damaged a barn and a shelterbelt.
An EF0 brief touchdown five miles northeast of Raymond and luckily did no damage. An EF1 near Twin Brooks crossed US Highway 12 and caused damage to a shelterbelt, grain bins, and a pole barn. This tornado had winds of 100mph and traveled over a mile.
The second round of tornadoes came on Memorial Day as severe thunderstorms developed over the eastern half. An EF1 tornado briefly touched down in the southwest part of Sioux Falls with peak winds of 90mph. The tornado only traveled 0.34 of a mile but caused damage to trees and some residential structures. Towards the east, an EF1 tornado touched down in Brandon doing damage to multiple trees and destroying the roof of a church.
Up in the northeast, the strongest tornado between the two events occurred in Deuel County. An EF3 tornado with winds of 140mph touched down about five miles south of Goodwin and traveled over 10miles to about one mile north of Tunerville. During its travel, a grain bin was ripped from the base and tossed a mile, a farmstead lost several outbuildings and their home and a transmission tower was completely twisted.
Photo Credit: National Weather Service - Deuel County, SD
An EF2 traveled just under 12 miles damaging a couple of silos, a barn, and a grain bin. This twister started about eight miles northeast of Estelline and ended about two miles southeast of Altamont. The peak winds were 115mph and the tornado was about 150 yards wide.
A quick touchdown of an EF1 was reported three miles northwest of Clear Lake tossing farm machinery and damaging trees. An eyewitness saw a quick spin-up of an EF0 tornado about four miles northeast of Stone Bridge doing minor damage to a cattle shed.
A long track, EF1 tornado started four miles southwest of La Bolt in Grant County and traveled for over ten miles to near Albee, SD. A farmstead had its roof torn off, along with damage to a shed, silo, and grain bin and another residence had half a barn roof ripped off. The peak winds of 100mph were reported and the width of the twister was about 40 yards.
The last tornado survey by the National Weather Service occurred about four miles north of Albee and travel about four and a half miles to about five miles southeast of Milbank. Trees, a home, and a barn were damaged by the EF1 tornado with wind speeds up to 100mph.