Late-May 2010 tornado outbreak

The Late-May 2010 tornado outbreak was a tornado outbreak that begun on May 22, and ended May 25, 2010. The storm system responsible for the tornadoes affected a large area from North Dakota to New Mexico. The system that caused the outbreak formed from a low-pressure system that was located in Canada.

Meteorological synopsis

On May 20, a strong low pressure system moved on to the British Columbia coast, bringing with it a cold front over the Rockies, although it produced no showers. Two days later, on May 22, the cold front detached from the low pressure system and connected with a warm front from the Southeastern United States and another low pressure system over Wyoming. Dry line activity increased over the Great Plains and many tornadoes formed in South Dakota. [2010 Bowdle, South Dakota|Bowdle tornado|The worst of these tornadoes] was rated an EF4 pending further analysis. The next day, on May 23, the warm front joined a portion of the cold front and became an occluded front. The cold front once again joined the Canadian low pressure system. Dry line activity held steady and a number of more tornadoes formed across the Great Plains. Many meteorologists believed that Monday, May 24 would be one of the most active tornado days. Dr. Greg Forbes of the Weather Channel issued an ⁸/₁₀ risk of tornadoes for spots in the Great Plains. A front was stationed over South Dakota, bringing fast moving supercells and tornadoes from North Dakota to Texas. The next day, more severe thunderstorms fired up, but severe activity shifted east and south. VORTEX2 was able to get valuable information when tracking a supercell that produced 3 tornadoes, each weak and short-lived.

Confirmed tornadoes

Bowdle, South Dakota

The tornado first touched down by a farmstead in eastern Walworth County, approximately away from Bowdle. At the time of the tornado touching down, the parent supercell was in the process of cycling. A 2010 study produced by numerous scientists, including tornado researcher Tim Samaras, determined that the tornado was likely a smaller condensation funnel within a larger area of circulation, but began to rapidly intensify and became the dominant funnel as it crossed South Dakota Highway 79. The visible funnel of the tornado centered itself in proportion to the supercell's mesocyclone as it moved to the northeast; a multiple-vortex structure was documented within the tornado.
Immediately at EF2 intensity, several outbuildings were severely damaged with the residence sustaining siding and roof damage. A stock trailer was thrown about from its original location. Tree damage was sustained on the west side of the property. The tornado continued moving northeast crossing into Edmunds County, where it then briefly weakened to EF1 strength, where it snapped and broke power poles. At the first farm, several large cottonwood trees were uprooted along with damage to several trailers. Three grain bins were also destroyed. The residence suffered some shingle and antenna damage. The tornado then abruptly weakened over a span of thirty seconds, losing a visible condensation funnel. At this point, the tornado was estimated to have been in width.
The tornado rapidly intensified as it moved to the northeast, quickly intensifying to EF3 strength where it impacted a second farm northwest of Bowdle. At this farmstead, several outbuildings were damaged or destroyed along with widespread tree damage. The main residence at this location suffered no damage. Several grain cars were also rolled about into the trees behind the house. As the tornado exited this farmstead, it intensified to EF4 strength before tearing through a third farmstead. At this farm, the main residence suffered major damage to walls with part of the roof removed.
Widespread tree damage was sustained with many of the trees completely debarked with only the stumps of the largest branches remaining. Two large garages were completely destroyed with the concrete slab wiped clean. The vehicles in one garage were rolled or tossed from to yards away. Another vehicle flew through the air before resting in a tree shelter belt to the north of the residence. Several other outbuildings were completely destroyed.The tornado then toppled six to eight metal power transmission towers as it moved to the north of the farm. One tower was sheared off from the concrete footings and was thrown an estimated. Ground scouring was visible along the path of these towers. The large tornado began to track east, declining to EF2 intensity before crossing over SD-47 where a state radio tower was toppled. The tornado lifted a short time later. The tornado was the first to be rated EF4 in South Dakota history since 2003.