Back-to-back powerful Pacific storm systems to impact the Pacific Northwest and northern California through the end of this week with heavy rain, flooding, strong winds, and higher elevation mountain snow. A strong, long-duration atmospheric river will accompany the Pacific storms, bringing excessive rainfall and flash flooding to southwest Oregon and northwest California through the week. Read More >
Overview
Saturday, October 9th and Wednesday, October 13th (a school day) both featured several tornadoes across eastern South Dakota and west-central Minnesota, which is a fairly rare occurrence for this area in October. See the Historical Perspective tab below for additional details. On October 9th, a late-season quasi-linear convective system (QLCS) produced severe weather and heavy rain. As the storm moved to the east-northeast across the area, it produced straight-line winds of 60 to 75 mph, along with 5 tornadoes (3 in SD and 2 in west central MN) across our forecast area. While most of these tornadoes were only briefly on the ground, one tornado near Dumont, MN traveled for around a mile and crossed through two farms, producing tree and building damage (rated EF-0). Then on October 13th, a strong low pressure system, which brought over a foot of snow to some locations in the Black Hills, produced 9 tornadoes (4 in SD and 5 in west central MN) across our forecast area. These tornadoes were associated with a line of low-topped thunderstorms that developed along an occluded front that was lifting north into a highly sheared and sufficiently unstable environment (sunshine broke out for a time following an extended period of steady morning rainfall). The tornadoes largely occurred between 3:00 and 4:30 pm in Roberts County, South Dakota and Big Stone and Traverse Counties in Minnesota. While most of these tornadoes did little to no damage, two tornadoes to the east and north of Wheaton, MN produced tree and building damage at a couple farms (both rated EF-1). We want to thank the storm spotters, emergency managers, and public for their reports both during and after these events. Your information helps us document the extent of these rare October tornado events. |
Tornado between Summit and Sisseton, SD, a little after 3 PM on October 13th, 2021 (Photo by Alex Resel) |
October 9th
Surface Weather Maps, Radar, Other
Surface observations at 1pm, 10-9-2021. Temperatures are in red, dewpoints in green, and pressure in yellow at each station | Surface observations at 4pm, 10-9-2021 | Surface observations at 7pm, 10-9-2021 | Surface observations at 10pm, 10-9-2021 |
Radar Reflectivity Loop from October 9, 2021: 1:00 PM CDT to 9:40 PM CDT | As storms approached Brentford, a tornado briefly touched down about 3 miles WSW of town in a bean field. The yellowish area that appears on the radar's Correlation Coefficient product on the right highlights lofted debris from this field. Radar loop is from 409 to 419pm. | Radar reflectivity across west central Minnesota at 721pm, around the time of a damaging tornado east northeast of Dumont | GOES-16 satellite (blend of visible and infrared) from 1pm to 8pm on October 9th, 2021 (20 minute time steps) from the CIRA RAMMB SLIDER |
Listing of some of the higher rainfall totals, as well as a radar-estimated totals map. Watertown set a daily record of 2.23" on Oct 9th, surpassing 1.51" in 1982. | The Willow Creek near Watertown rose to minor flood stage on the morning of Oct 10th in response to the heavy rain | The south branch tributary to Mud Creek near Rauville nearly rose to minor flood stage in response to the heavy rain | The Big Sioux River near Castlewood nearly rose to minor flood stage in response to the heavy rain |
Photos
Storm approaching Castlewood, SD on October 9, 2021 (Photo by Derek Thompson) |
Straight-line wind damage in Groton | Flooding in Watertown, SD. (Photo from KXLG-Watertown) |
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Tornado damage to a farm building 2 miles to the southwest of Dumont, MN on October 9, 2021. (Photo by Nick and Amanda Elms) |
Uprooted tree from a tornado 2 miles to the southwest of Dumont, MN. (Photo by Nick and Amanda Elms) |
Tornado left debris in a field 2 miles to the southwest of Dumont, MN. (Photo by Nick and Amanda Elms) |
Tornado damage 2 miles to the southwest of Dumont, MN on October 9, 2021. (Photo by Nick and Amanda Elms) |
Tornado damage to a farm silo east northeast of Dumont, MN. Photo from the official NWS storm survey | The missing silo in the photo to the left was transported by the tornado across the field into another property. Photo from the official NWS storm survey | Tornado damage to a farm building east northeast of Dumont, MN. Photo from the official NWS storm survey | One of the missing metal roof panels from the photo to the left. Photo from the official NWS storm survey |
October 13th
Surface Weather Maps, Radar, Other
Surface observations at 10am, 10-13-2021. Temperatures are in red, dewpoints in green, and pressure in yellow at each station | Surface observations at 1pm, 10-13-2021 | Surface observations at 4pm, 10-13-2021 | Surface observations at 7pm, 10-13-2021. Temperatures dropped into the 40s at Wheaton, MN by the morning of the 14th |
Radar Reflectivity Loop from October 13, 2021: 1:00 PM CDT to 5:00 PM CDT | Radar reflectivity (left) and storm relative velocity (right) across west central Minnesota at 420pm, at the time of a damaging tornado north of Wheaton | Radar reflectivity (left) and storm relative velocity (right) across west central Minnesota at 422pm, at the time of a damaging tornado east of Wheaton | GOES-16 satellite (blend of visible and infrared) from 1pm to 445pm on October 13th, 2021 (10 minute time steps) from the CIRA RAMMB SLIDER |
List of some of the highest 48 hour rainfall totals across central & northeastern SD and west central MN | Radar-estimated 48 hour rainfall totals | List of some of the highest non-thunderstorm wind gusts across central & northeastern SD, associated with the deep surface low | Snowfall amounts across the Black Hills of South Dakota and region. More information from the Rapid City, SD NWS office here |
Photos
Two landspout funnels (one briefly touched down) located 4 miles west of Onida at approximately 1:15 PM. (Photo from Sully County EM) |
Tornado occurring in Big Stone County around or after 3:40 PM on October 13, 2021 (Photo from Big Stone County Sheriff's Office) | Tornado occurring in Big Stone County around or after 3:40 PM (Photo from Big Stone County Sheriff's Office) |
Tornado 4 miles west of Clinton, MN at 3:42 PM (Photo by Jason Haugen, relayed by Nick and Amanda Elms) |
Tornado about 4 miles south of Barry, MN around 345pm. (Photo courtesy of Dusty Escher) | Tornado about 4 miles south of Barry, MN around 345pm. (Photo courtesy of Dusty Escher) | Tornado spotted north of Milbank. (Photo from Matthew Wohlleber). Note, tornadoes can and did develop in close proximity to blue skies, being on the edge of relatively small storms. | Debris from a tornado at 427pm 6 to 7 miles west of Herman, MN. (Photo courtesy of Preston Lund) |
Tornado damage to a tree at a farm north of Wheaton, MN. Photo from the official NWS storm survey | Tornado damage to a farm building north of Wheaton, MN. Photo from the official NWS storm survey | Tornado damage to a farm building north of Wheaton, MN. Photo from the official NWS storm survey | A convergent wind pattern in the corn stocks from where the tornado north of Wheaton, MN entered. Photo from the official NWS storm survey |
Tornado damage to trees on a farm east of Wheaton, MN. Photo from the official NWS storm survey | Tornado damage to a farm building east of Wheaton, MN. Photo from the official NWS storm survey | The tornado shifted heavy farm equipment east of Wheaton, MN. Photo from the official NWS storm survey | Tornado damage to farm equipment east of Wheaton, MN. Photo from the official NWS storm survey |
October 9th Storm Reports
The map below can be found in an interactive form here.
An official NWS survey crew documented the following tornado from October 9th. Additional tornado and other severe weather reports can be found listed further down the page. Information is preliminary.
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0412 PM Tornado 2 SW Brentford 45.14N 98.35W
10/09/2021 Spink SD Trained Spotter
12 large hay bales were rolled some distance, including over a fence. Time
estimated based on radar. Secondary public report of brief tornado southwest of
Brentford in an open field.
0425 PM Tstm Wnd Gst 6 ENE Brentford 45.18N 98.21W
10/09/2021 E75 MPH Spink SD Trained Spotter
0436 PM Tstm Wnd Gst 3 ESE Aberdeen 45.45N 98.41W
10/09/2021 M56 MPH Brown SD Official NWS Obs
0510 PM Tstm Wnd Gst Andover 45.41N 97.90W
10/09/2021 M66 MPH Day SD Mesonet
Corrects previous non-tstm wnd gst report from Andover. Mesonet station 45 Andover
(SDDOT).
0512 PM Tornado 3 W Langford 45.60N 97.88W
10/09/2021 Marshall SD Emergency Mngr
0529 PM Tstm Wnd Gst 6 W Henry 44.88N 97.58W
10/09/2021 M57 MPH Clark SD Mesonet
Corrects previous non-tstm wnd gst report from 6 W Henry. Mesonet station 174 Clark (SDDOT).
0531 PM Tornado 2 NW Roslyn 45.52N 97.52W
10/09/2021 Day SD Fire Dept/Rescue
Fire Department report a brief tornado touchdown. Time estimated.
0535 PM Tstm Wnd Dmg Roslyn 45.50N 97.49W
10/09/2021 Day SD Fire Dept/Rescue
Trees down in Roslyn. Estimated 60 to 70 mph winds.
0605 PM Funnel Cloud 2 W Ortley 45.34N 97.24W
10/09/2021 Day SD Public
0615 PM Tstm Wnd Dmg Bryant 44.59N 97.47W
10/09/2021 Hamlin SD Public
Tree damage in Bryant. Time estimated.
0628 PM Hail 4 W Hayti 44.66N 97.29W
10/09/2021 M1.00 inch Hamlin SD Trained Spotter
0636 PM Tstm Wnd Dmg 3 NW Peever 45.57N 96.99W
10/09/2021 Roberts SD Emergency Mngr
30 foot trailer pulled by a pick up truck overturned on Interstate 29. Time estimated by radar.
0638 PM Hail 2 S Thomas 44.73N 97.20W
10/09/2021 E1.00 inch Hamlin SD Trained Spotter
0718 PM Tornado 2 SW Dumont 45.70N 96.45W
10/09/2021 Traverse MN Public
Corrects previous tstm wnd dmg report from 2 SW Dumont. A tornado caused damage to a
barn. The winds damaged a wall, and unroofed part of the barn. Time estimated based on
radar.
0721 PM Tornado 7 ENE Dumont 45.76N 96.29W
10/09/2021 Traverse MN NWS Storm Survey
Damage to trees, grain bins and out buildings. See official NWS damage survey
for more information.
October 13th Storm Reports
The map below can be found in an interactive form here.
An official NWS survey crew documented the following tornadoes from October 13th. Additional tornado and other severe weather reports can be found listed further down the page. Information is preliminary. ..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON... ..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE.... ..REMARKS.. 0115 PM Funnel Cloud 1 SW Onida 44.69N 100.09W 10/13/2021 Sully SD Emergency Mngr Emergency Manager relayed a report of a funnel cloud made by the public. Storm in that area also producing pea size hail. 0115 PM Tornado 2 SW Onida 44.69N 100.09W 10/13/2021 Sully SD Emergency Mngr Emergency Manager relayed a report of a funnel cloud made by the public. This funnel cloud made very brief contact with the ground. 0117 PM Funnel Cloud 5 NE Grey Goose 44.55N 100.28W 10/13/2021 Sully SD Trained Spotter Approximate time and location, relayed via social media with photos. 0303 PM Tornado 3 NE Rudebusch Corner 45.46N 97.10W 10/13/2021 Roberts SD Trained Spotter Approximate tornado begin time and location based on report and radar. The tornado lasted for about 5 minutes. 0315 PM Tstm Wnd Gst Lake City 45.72N 97.42W 10/13/2021 M56 MPH Marshall SD Mesonet Mesonet station 2 Lake City (SDDOT). 0325 PM Tornado 5 ENE Wilmot 45.44N 96.76W 10/13/2021 Roberts SD Public Approximate location and time. 0325 PM Tstm Wnd Gst 3 SW Big Stone City 45.27N 96.51W 10/13/2021 M57 MPH Grant SD Mesonet Mesonet station 292 7NE Milbank (SDDOT). 0330 PM Tornado 9 NW Big Stone City 45.40N 96.59W 10/13/2021 Roberts SD Trained Spotter A small waterspout tracked across Big Stone Lake. Approximate location based on report and radar. 0333 PM Tornado 3 N Odessa 45.30N 96.34W 10/13/2021 Big Stone MN Public Tornado observed with photo. Time approximated from radar. 0342 PM Tornado 4 NW Clinton 45.51N 96.50W 10/13/2021 Big Stone MN Fire Dept/Rescue Confirmed by Graceville Fire Department. Time approximated based on radar. 0346 PM Tornado 4 S Barry 45.50N 96.56W 10/13/2021 Big Stone MN Public Confirmed with pictures sent via social media. 0418 PM Tornado 9 NNW Wheaton 45.93N 96.55W 10/13/2021 Traverse MN NWS Storm Survey Damage to trees, a pole barn, and farm equipment. See official NWS damage survey for more information. 0422 PM Tornado 9 NE Dumont 45.80N 96.29W 10/13/2021 Traverse MN Law Enforcement Corrects previous tstm wnd dmg report from 9 NE Dumont. Uprooted tree and roof off an outbuilding, reported by Traverse County Sheriff. See PNS for NWS survey information.
Historical Perspective
Tornadoes in October are very infrequent, with the last October tornado in South Dakota or Minnesota occurring in 2013. Prior to 2021, there had been just 18 total confirmed October tornadoes in the state of South Dakota, and 29 in Minnesota (left two images below). The biggest October tornado outbreak in both Minnesota and South Dakota occurred on October 26, 1996, when a combined 24 tornadoes occurred (10 in SD and 14 in MN), and the year with the most October tornadoes for both states was also 1996 (10 in SD and 16 in MN). The October 9th and 13th, 2021 events combined for a preliminary total of 7 tornadoes in SD and 9 in MN, which ranks as the 2nd highest number of October tornadoes for both states since records began in 1950.
15 total Tornado Warnings were issued by NWS Aberdeen in October (right two images below), by far the largest number ever issued for the month, and similar to what we would normally issue during an active June or July. This is only the 5th time that a tornado warning was issued in October since record keeping began in 1986. The 12 tornado warnings issued on the *single day* of October 9th is higher than the *total monthly amount* for any August, September or October on record.
Listing of all documented South Dakota tornadoes in the month of October, prior to 10-9-2021, from Storm Data | Listing of all documented Minnesota tornadoes in the month of October, prior to 10-9-2021, from Storm Data | Chart of Tornado Warnings issued by NWS Aberdeen by month since 1986 (Iowa State - IEM) |
Chart of the first and last days that Tornado Warnings were issued by NWS Aberdeen and listed by year (Iowa State - IEM) |
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