Unusual warmth with a week of temperatures mainly in the 70s (even 50s and 60s on November 9 less than a day before this storm) was brought to an abrupt end as a deep trough of low pressure moved out of Rockies and into the Plains. An intense lower- to mid-level frontal zone oozed eastward as a strong jet lifted out across the Plains on November 10, initiating widespread precipitation. More rapid shallow cooling occurred across northwest Iowa and northeast Nebraska, and led to a swath of freezing rain which accumulated from a tenth to a half inch during the overnight and morning hours, before changing to snow in the afternoon. Heavier and more persistent snowfall occurred with the deeper cooling to the northwest across southeast South Dakota, far northwest Iowa and southwest Minnesota, where amounts ranged from 3 to 7 inches.

Winter Storm in UNION, SOUTH DAKOTA
From 10-NOV-20 07:30:00 to 10-NOV-20 17:00:00 (CST-6)
Reported by: CoCoRaHS

Snowfall started briefly as light freezing rain and sleet, with ice accumulation of less than a tenth of an inch during the early morning of November 10.  Snow was briefly heavy between 1100-1400. Total snowfall accumulation reached 6.2 inches 6 miles north northeast of Elk Point.

Winter Storm in CLAY, SOUTH DAKOTA
From 10-NOV-20 08:00:00 to 10-NOV-20 17:00:00 (CST-6)
Reported by: COOP Observer

Snowfall, briefly mixed with sleet or freezing drizzle during the morning, became heavy at times between 1100-1500CST.  Accumulations reached 6.7 inches at Vermillion and 6.0 inches 6 miles southeast of Centerville.

Winter Storm in YANKTON, SOUTH DAKOTA
From 10-NOV-20 08:00:00 to 10-NOV-20 17:00:00 (CST-6)
Reported by: COOP Observer

Snowfall, heavy at times between 1200-1500CST, accumulated to 8.0 inches at Yankton and 6.0 inches 1 mile west of Yankton.

Winter Storm in LINCOLN, SOUTH DAKOTA
From 10-NOV-20 08:00:00 to 10-NOV-20 18:00:00 (CST-6)
Reported by: COOP Observer

Snowfall, heavy at times between 1200-1600CST, accumulated to 6.5 inches 1 mile southeast of Tea and 6.4 inches at Canton.

Winter Storm in TURNER, SOUTH DAKOTA
From 10-NOV-20 08:00:00 to 10-NOV-20 18:00:00 (CST-6)
Reported by: COOP Observer

Snowfall, heavy at times between 1200-1600CST, accumulated to 7.0 inches at Parker, 6.6 inches at Hurley, and 5.5 inches at Marion.

Winter Storm in HUTCHINSON, SOUTH DAKOTA
From 10-NOV-20 08:30:00 to 10-NOV-20 18:00:00 (CST-6)
Reported by: COOP Observer

Snowfall, heavy at times between 1000-1300CST, accumulated to 7.0 inches 11 miles south of Emery and 6.0 inches at Menno.

Winter Storm in MINNEHAHA, SOUTH DAKOTA
From 10-NOV-20 09:00:00 to 10-NOV-20 18:30:00 (CST-6)
Reported by: CoCoRaHS

Snowfall, heavy at times between 1200-1600CST, accumulated to 7.0 inches on the west side of Sioux Falls, 6.5 inches 2 miles west southwest of Garretson, and 6.0 inches 4 miles northwest of Renner and 6 miles south of Hartford. Poor road conditions at the onset led to numerous accidents, one of which resulted in the (indirect) fatality of a driver and passenger of a pickup truck which lost control and collided with another vehicle before it rolled in the median.  The driver of the other vehicle suffered non-life threatening injuries.

Winter Storm in MCCOOK, SOUTH DAKOTA
From 10-NOV-20 09:00:00 to 10-NOV-20 18:30:00 (CST-6)
Reported by: CoCoRaHS

Snowfall, heavy at times between 1200-1600CST, accumulated to 6.5 inches 5 miles northeast of Salem and 5.5 inches 6 miles northwest of Montrose.

Winter Weather in BROOKINGS, SOUTH DAKOTA
From 10-NOV-20 10:00:00 to 10-NOV-20 19:00:00 (CST-6)
Reported by: COOP Observer

Snowfall totaled 5.6 inches at Brookings, 5.0 inches at Aurora, and 4.0 inches at White.

Winter Weather in HANSON, SOUTH DAKOTA
From 10-NOV-20 09:00:00 to 10-NOV-20 17:00:00 (CST-6)
Reported by: COOP Observer

Snowfall totaled 4.5 inches at Alexandria.

Winter Weather in LAKE, SOUTH DAKOTA
From 10-NOV-20 09:30:00 to 10-NOV-20 18:30:00 (CST-6)
Reported by: COOP Observer

Snowfall totaled 5.4 inches 2 miles north of Chester and 4.0 inches at Madison.

Winter Weather in BON HOMME, SOUTH DAKOTA
From 10-NOV-20 08:00:00 to 10-NOV-20 16:30:00 (CST-6)
Reported by: COOP Observer

Snowfall totaled 5.5 inches 8 miles west northwest of Springfield and 4.8 inches at Tyndall.

Winter Weather in MOODY, SOUTH DAKOTA
From 10-NOV-20 09:30:00 to 10-NOV-20 19:00:00 (CST-6)
Reported by: COOP Observer

Snowfall totaled 5.0 inches 8 miles south of Brookings and 4.7 inches at Flandreau.