SIOUX FALLS, S.D. (KELO) — Monday’s storm system produced two tornadoes in Gregory County and a third near Alvord, Iowa, in Lyon County, the National Weather Service said on Thursday. The Iowa tornado traveled about two miles while the other two tornadoes covered combined 20 miles in Gregory County.
An isolated storm in central South Dakota produced one tornado about a mile northwest of Dixon. Dixon is an unincorporated town in Gregory County. This was an EF-1 tornado that damaged a farm outbuilding, some power poles and a South Dakota Department of Transportation truck shelter. The NWS said this tornado happened about 4:28 p.m. and lasted about 20 minutes over 11 miles.
The second tornado happened about 5:38 p.m. and was about eight miles northwest of Bonesteel, and not farm from the city of Gregory, both in Gregory County. The NWS said this was an EF-2 tornado that damaged a single family home, two outbuildings, a camper and an abandoned trailer. It also damaged power poles. This tornado traveled about eight miles and last about 45 minutes.
According to the NWS and EF-1 tornado has wind speeds of 86-110 mph. An EF-2 tornado has wind speeds of 111-135 mph.
Gregory County’s emergency manager Brad Christensen told KELOLAND News on Tuesday he and NWS were still uncertain on Tuesday if the county had two tornadoes. Local firefighters were battling fires started by storm lightning while also tracking one tornado that traveled between two groups of firefighters.
The third tornado was an EF-1 about one mile east of Alvord, Iowa. It damaged some farm buildings, a larage barn and a grove of trees, the NWS said. This tornado happened at 9:30 p.m. and lasted about one minute. It traveled 1.7 miles.
Heading into Monday afternoon, there was discussion of a possible derecho in southeastern South Dakota and northwestern Iowa.
Although the storm system produced two tornadoes in South Dakota, as the system formed storms and passed through areas near Chamberlain, Gregory County and others, the NWS said the storm system did not transform into a deroche until later Monday evening.
In this deroche, wind gusts of 55 to 99 mph were common across the southeastearn quarter of South Dakota and the northern half of Iowa, according to the NWS.
“The greatest concentration of wind damage was near a line from Beresford to Spencer, Iowa,” the NWS said. Numerous reports of strong wind gusts and photos of structural damage were collected across the area.
The NWS recorded a wind gust of 99 mph Monday near Sioux Center, Iowa.
A co-owner of a car wash and welding shop business in Alvord told KELOLAND News on Tuesday about the damage.
“We’ve just been cleaning up, trying to salvage what we can,” co-owner Rachel Garland said. “There’s really nothing that is salvageable. We have a part-time employee. We have two welders. We just were trying to buy a plasma table, and our entire shop is gone.”
Hudson was also impacted by Monday’s storm and the NWS-now declared deroche. The storm left uprooted trees, broken trees and damaged buildings behind.
“Everyone was affected, no one was spared,” said Steve Wickre, Hudson’s mayor, told KELOLAND News on Tuesday.
The NWS reported on Wednesday that a Sunday tornado near Watertown in Codington County traveled four miles. It destroyed a house, some outbuildings and trees on a farm. This was an EF-2 tornado with a top wind speed of 135 mph.
