A potent and persistent outbreak of Arctic air affected the entire region from February 6th through the 17th. The coldest days of the outbreak for many occurred Valentine's Day weekend, when high temperatures averaged around ten below zero, in northeastern South Dakota, to the single digits above zero, in central South Dakota. On February 14th, low temperatures dropped into the 20s to the 30s degrees below zero range. Extreme wind chills of 35 degrees to 55 degrees below zero also occurred on several days during the outbreak.

The magnitude of the cold during this outbreak was fairly rare compared to the past 50 years, at least in terms of the persistence of the Arctic air. This was especially impressive considering the lack of deep, fresh snow cover across most of the area. If there had been widespread deep, fresh snowpack ahead of this Arctic outbreak, low temperatures would have been more severe and more often approaching record territory. Even with the lack of snow cover, Pierre dropped to 20 degrees below zero or colder on the 14th and 15th. Since 1934, Pierre has had two other occurrences when the low temperature fell to 20 degrees below zero with no snow cover. The previous days were January 24th, 1961, and January 5th, 1979.
Impacts from this extreme and persistent cold include many frozen and/or broken water pipes (the limited snow depth did not help in this regard) and froze-over home sewer vents, dead vehicle batteries, school delays, and church cancellations. The prolonged cold caused significant strains to the power grid as demand spiked both locally and across several other states. Thousands of customers were at least briefly without power locally, particularly during the morning of Tue, Feb 16th. Concerns for rolling blackouts lingered for several days in this regard due to the continued extreme demand/strain, and people were repeatedly asked to conserve energy however possible.

Extreme Cold/Wind Chill in DEWEY, SOUTH DAKOTA
From 06-FEB-21 00:00:00 to 17-FEB-21 23:59:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Extreme Cold/Wind Chill in WALWORTH, SOUTH DAKOTA
From 06-FEB-21 00:00:00 to 17-FEB-21 23:59:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Extreme Cold/Wind Chill in LYMAN, SOUTH DAKOTA
From 06-FEB-21 00:00:00 to 17-FEB-21 23:59:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Extreme Cold/Wind Chill in HAND, SOUTH DAKOTA
From 06-FEB-21 00:00:00 to 17-FEB-21 23:59:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Extreme Cold/Wind Chill in CLARK, SOUTH DAKOTA
From 06-FEB-21 00:00:00 to 17-FEB-21 23:59:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Extreme Cold/Wind Chill in CORSON, SOUTH DAKOTA
From 06-FEB-21 00:00:00 to 17-FEB-21 23:59:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Extreme Cold/Wind Chill in STANLEY, SOUTH DAKOTA
From 06-FEB-21 00:00:00 to 17-FEB-21 23:59:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Extreme Cold/Wind Chill in POTTER, SOUTH DAKOTA
From 06-FEB-21 00:00:00 to 17-FEB-21 23:59:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Extreme Cold/Wind Chill in MCPHERSON, SOUTH DAKOTA
From 06-FEB-21 00:00:00 to 17-FEB-21 23:59:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Extreme Cold/Wind Chill in BUFFALO, SOUTH DAKOTA
From 06-FEB-21 00:00:00 to 17-FEB-21 23:59:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Extreme Cold/Wind Chill in HAMLIN, SOUTH DAKOTA
From 06-FEB-21 00:00:00 to 17-FEB-21 23:59:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Extreme Cold/Wind Chill in CAMPBELL, SOUTH DAKOTA
From 06-FEB-21 00:00:00 to 17-FEB-21 23:59:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Extreme Cold/Wind Chill in SULLY, SOUTH DAKOTA
From 06-FEB-21 00:00:00 to 17-FEB-21 23:59:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Extreme Cold/Wind Chill in EDMUNDS, SOUTH DAKOTA
From 06-FEB-21 00:00:00 to 17-FEB-21 23:59:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Extreme Cold/Wind Chill in BROWN, SOUTH DAKOTA
From 06-FEB-21 00:00:00 to 17-FEB-21 23:59:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

Extreme Cold/Wind Chill in CODINGTON, SOUTH DAKOTA
From 06-FEB-21 00:00:00 to 17-FEB-21 23:59:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Extreme Cold/Wind Chill in HUGHES, SOUTH DAKOTA
From 06-FEB-21 00:00:00 to 17-FEB-21 23:59:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Extreme Cold/Wind Chill in FAULK, SOUTH DAKOTA
From 06-FEB-21 00:00:00 to 17-FEB-21 23:59:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Extreme Cold/Wind Chill in SPINK, SOUTH DAKOTA
From 06-FEB-21 00:00:00 to 17-FEB-21 23:59:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Extreme Cold/Wind Chill in DEUEL, SOUTH DAKOTA
From 06-FEB-21 00:00:00 to 17-FEB-21 23:59:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Extreme Cold/Wind Chill in HYDE, SOUTH DAKOTA
From 06-FEB-21 00:00:00 to 17-FEB-21 23:59:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Extreme Cold/Wind Chill in MARSHALL, SOUTH DAKOTA
From 06-FEB-21 00:00:00 to 17-FEB-21 23:59:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Extreme Cold/Wind Chill in ROBERTS, SOUTH DAKOTA
From 06-FEB-21 00:00:00 to 17-FEB-21 23:59:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Extreme Cold/Wind Chill in DAY, SOUTH DAKOTA
From 06-FEB-21 00:00:00 to 17-FEB-21 23:59:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Extreme Cold/Wind Chill in GRANT, SOUTH DAKOTA
From 06-FEB-21 00:00:00 to 17-FEB-21 23:59:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Extreme Cold/Wind Chill in JONES, SOUTH DAKOTA
From 06-FEB-21 00:00:00 to 17-FEB-21 23:59:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer