A massive arctic plunge into the Northern Plains brought almost a week of dangerous and life threatening wind chills to the region. The worst conditions were recorded between February 13 and February 16 when wind chills occasionally dropped as low as 35 below to 55 below zero.  Numerous record low maximum and minimum temperatures were also established.  The areal extent of the extreme cold in the central portions of the U.S. led to stress on the power grid, which necessitated several short-term rolling power outages impacting more than 10,000 customers during the peak of the cold.

Extreme Cold/Wind Chill in CHARLES MIX, SOUTH DAKOTA
From 14-FEB-21 03:00:00 to 16-FEB-21 08:00:00 (CST-6)
Reported by: RAWS

During several periods over three days with wind chill below -35, values reached a minimum of -42 5 miles west of Geddes, -39 10 miles west of Platte, and -37 at Platte.

Extreme Cold/Wind Chill in BON HOMME, SOUTH DAKOTA
From 14-FEB-21 02:00:00 to 16-FEB-21 10:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

During several periods over three days with wind chill below -35, values reached a minimum of -44 near Tyndall.

Extreme Cold/Wind Chill in AURORA, SOUTH DAKOTA
From 14-FEB-21 00:00:00 to 16-FEB-21 10:00:00 (CST-6)
Reported by: Mesonet

During several periods over three days with wind chill below -35, values reached a minimum of -43 3 miles west of Plankinton and -41 at White Lake.

Extreme Cold/Wind Chill in DAVISON, SOUTH DAKOTA
From 14-FEB-21 03:00:00 to 16-FEB-21 07:00:00 (CST-6)
Reported by: ASOS

During several periods over three days with wind chill below -35, values reached a minimum of -39 at Mitchell and -38 at Ethan.

Extreme Cold/Wind Chill in YANKTON, SOUTH DAKOTA
From 14-FEB-21 05:00:00 to 16-FEB-21 09:00:00 (CST-6)
Reported by: AWOS

During several periods over three days with wind chill below -35, values reached a minimum of -43 near Gayville and -42 at Yankton.

Extreme Cold/Wind Chill in HUTCHINSON, SOUTH DAKOTA
From 14-FEB-21 01:00:00 to 16-FEB-21 10:00:00 (CST-6)
Reported by: Mesonet

During several periods over three days with wind chill below -35, values reached a minimum of -45 near Freeman, -43 near Tripp and -42 at Parkston.

Extreme Cold/Wind Chill in HANSON, SOUTH DAKOTA
From 14-FEB-21 02:00:00 to 16-FEB-21 09:00:00 (CST-6)
Reported by: Department of Highways

During several periods over three days with wind chill below -35, values reached a minimum of -43 near Alexandria.

Extreme Cold/Wind Chill in MCCOOK, SOUTH DAKOTA
From 14-FEB-21 00:00:00 to 16-FEB-21 10:00:00 (CST-6)
Reported by: Department of Highways

During several periods over three days with wind chill below -35, values reached a minimum of -45 near Montrose and -37 at Canova.

Extreme Cold/Wind Chill in DOUGLAS, SOUTH DAKOTA
From 14-FEB-21 02:00:00 to 16-FEB-21 09:00:00 (CST-6)
Reported by: Mesonet

During several periods over three days with wind chill below -35, values reached a minimum of -45 at Parkston and -37 at Platte.

Extreme Cold/Wind Chill in LINCOLN, SOUTH DAKOTA
From 14-FEB-21 01:00:00 to 16-FEB-21 10:00:00 (CST-6)
Reported by: Department of Highways

During several periods over three days with wind chill below -35, values reached a minimum of -47 5 miles east of Davis.

Extreme Cold/Wind Chill in SANBORN, SOUTH DAKOTA
From 14-FEB-21 00:00:00 to 16-FEB-21 07:00:00 (CST-6)
Reported by: Department of Highways

During several periods over three days with wind chill below -35, values reached a minimum of -40 4 miles east southeast of Forestburg.

Extreme Cold/Wind Chill in JERAULD, SOUTH DAKOTA
From 14-FEB-21 00:00:00 to 16-FEB-21 08:00:00 (CST-6)
Reported by: RAWS

During several periods over three days with wind chill below -35, values reached a minimum of -42 17 miles south southwest of Wessington.

Extreme Cold/Wind Chill in MINER, SOUTH DAKOTA
From 14-FEB-21 01:00:00 to 16-FEB-21 09:00:00 (CST-6)
Reported by: Department of Highways

During several periods over three days with wind chill below -35, values reached a minimum of -44 1 mile west of Howard.

Extreme Cold/Wind Chill in LAKE, SOUTH DAKOTA
From 13-FEB-21 22:30:00 to 16-FEB-21 07:00:00 (CST-6)
Reported by: AWOS

During several periods over three days with wind chill below -35, values reached a minimum of -45 at Madison.

Extreme Cold/Wind Chill in MOODY, SOUTH DAKOTA
From 13-FEB-21 20:00:00 to 16-FEB-21 09:00:00 (CST-6)
Reported by: Mesonet

During several periods over three days with wind chill below -35, values reached a minimum of -47 13 miles west of Ward and -45 at Flandreau.

Extreme Cold/Wind Chill in BRULE, SOUTH DAKOTA
From 14-FEB-21 03:00:00 to 16-FEB-21 11:00:00 (CST-6)
Reported by: Department of Highways

During several periods over three days with wind chill below -35, values reached a minimum of -43 near Kimball and -38 at Chamberlain.

Extreme Cold/Wind Chill in GREGORY, SOUTH DAKOTA
From 14-FEB-21 02:00:00 to 16-FEB-21 01:00:00 (CST-6)
Reported by: Department of Highways

During several periods over three days with wind chill below -35, values reached a minimum of -42 at Fort Randall Dam, -41 2 miles north of Bonesteel and -39 10 miles north of Gregory.

Extreme Cold/Wind Chill in CLAY, SOUTH DAKOTA
From 14-FEB-21 03:00:00 to 16-FEB-21 09:00:00 (CST-6)
Reported by: Mesonet

During several periods over three days with wind chill below -35, values reached a minimum of -49 5 miles southeast of Centerville.

Extreme Cold/Wind Chill in UNION, SOUTH DAKOTA
From 14-FEB-21 02:00:00 to 16-FEB-21 10:00:00 (CST-6)
Reported by: Department of Highways

During several periods over three days with wind chill below -35, values reached a minimum of -42 3 miles south of Beresford and -41 at North Sioux City.

Extreme Cold/Wind Chill in TURNER, SOUTH DAKOTA
From 14-FEB-21 01:00:00 to 16-FEB-21 10:00:00 (CST-6)
Reported by: Department of Highways

During several periods over three days with wind chill below -35, values reached a minimum of -46 1 mile south of Centerville.

Extreme Cold/Wind Chill in BEADLE, SOUTH DAKOTA
From 13-FEB-21 22:00:00 to 16-FEB-21 07:00:00 (CST-6)
Reported by: ASOS

During several periods over three days with wind chill below -35, values reached a minimum of -44 near Wolsey, -42 at Huron and -41 at Cavour.

Extreme Cold/Wind Chill in KINGSBURY, SOUTH DAKOTA
From 14-FEB-21 00:00:00 to 16-FEB-21 07:00:00 (CST-6)
Reported by: Department of Highways

During several periods over three days with wind chill below -35, values reached a minimum of -46 near Arlington.

Extreme Cold/Wind Chill in BROOKINGS, SOUTH DAKOTA
From 13-FEB-21 22:00:00 to 16-FEB-21 07:00:00 (CST-6)
Reported by: AWOS

During several periods over three days with wind chill below -35, values reached a minimum of -46 near Oak Lake, -45 at Brookings and -42 at Volga.

Extreme Cold/Wind Chill in MINNEHAHA, SOUTH DAKOTA
From 14-FEB-21 02:00:00 to 16-FEB-21 07:00:00 (CST-6)
Reported by: ASOS

During several periods over three days with wind chill below -35, values reached a minimum of -46 near Dell Rapids, -43 at Baltic and Colton, and -42 at Sioux Falls.  Brandon Valley high school students were forced to move into the gymnasium and other windowless rooms to maintain warmth when a rolling blackout caused a power outage for several hours.