A large upper level low pressure area developed across Kansas and lifted into Iowa by December 2.  The leading edge of the system produced some light ice accumulations from southeast South Dakota into northwest Iowa on early Saturday morning.  Heavy snow and wind developed during Saturday and Saturday evening, but a weak downslope impact reduced snow amounts closer to Interstate 29 in eastern South Dakota.

Winter Storm in DOUGLAS, SOUTH DAKOTA
From 01-DEC-18 05:00:00 to 02-DEC-18 08:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

After a brief period of freezing rain which produced a glaze of light icing during the early morning of December 1, heavy snow occurred for numerous hours. Accumulations over  less than a 24-hour period totaled 7.5 inches 1 mile south of Armour. Winds gusted to 30 to 40 mph and combined with snowfall to produce several hours of visibility of a half mile or less along with treacherous travel.

Winter Storm in UNION, SOUTH DAKOTA
From 01-DEC-18 03:00:00 to 02-DEC-18 02:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: CoCoRaHS

After a brief period of freezing rain which produced a glaze of light icing during the early morning of December 1, heavy snow occurred for numerous hours. Accumulations over less than a 24-hour period totaled 8.0 inches six miles south of Alcester and 6.8 inches six miles north of Elk Point. Winds gusted to 30 to 40 mph and combined with snowfall to produce several hours of visibility of a half mile or less along with treacherous travel. Numerous cars slid into the ditch along Interstate 29, but no significant damage was reported.

Winter Storm in DAVISON, SOUTH DAKOTA
From 01-DEC-18 04:00:00 to 02-DEC-18 07:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Official NWS Observations

After a brief period of freezing rain which produced a glaze of light icing during the early morning of December 1, heavy snow occurred for numerous hours. Accumulations over  less than a 24-hour period totaled 6.7 inches at Mitchell and 6.0 inches 6 miles north northwest of Ethan. Winds gusted to 30 to 40 mph and combined with snowfall to produce several hours of visibility of a half mile or less along with treacherous travel.

Winter Storm in GREGORY, SOUTH DAKOTA
From 01-DEC-18 04:00:00 to 02-DEC-18 07:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

After a brief period of freezing rain which produced a glaze of light icing during the early morning of December 1, heavy snow occurred for numerous hours.  With temperatures near freezing, snowfall was greatly elevation dependent, with amounts over less than 24 hours from 17.1 inches 2 miles northeast of Burke and 13.5 inches at Gregory, to 7.4 inches 4 miles south southwest of Pickstown.  Winds gusted to 30 to 40 mph from 1800CST December 1 to 0300CST December 2, producing periods of visibility of a half mile or less and treacherous travel conditions.

Winter Storm in HUTCHINSON, SOUTH DAKOTA
From 01-DEC-18 06:00:00 to 02-DEC-18 09:30:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

After a brief period of freezing rain which produced a glaze of light icing during the early morning of December 1, heavy snow occurred for numerous hours. Accumulations over less than a 24-hour period totaled 7.0 inches at Menno and 6.5 inches at Parkston. Winds gusted to 30 to 40 mph and combined with snowfall to produce several hours of visibility of a half mile or less along with treacherous travel.

Winter Storm in BON HOMME, SOUTH DAKOTA
From 01-DEC-18 06:00:00 to 02-DEC-18 09:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

After a brief period of freezing rain which produced a glaze of light icing during the early morning of December 1, heavy snow occurred for numerous hours. Accumulations over less than a 24-hour period totaled 8.3 inches at Tyndall and 7.0 inches 7 miles south of Avon. Winds gusted to 30 to 40 mph and combined with snowfall to produce several hours of visibility of a half mile or less along with treacherous travel.

Winter Storm in CHARLES MIX, SOUTH DAKOTA
From 01-DEC-18 05:00:00 to 02-DEC-18 09:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

After a brief period of freezing rain which produced a glaze of light icing during the early morning of December 1, heavy snow occurred for numerous hours. Accumulations over less than a 24-hour period totaled 10.5 inches near Wagner.  Winds gusted to 30 to 35 mph and combined with snowfall to produce several hours of visibility of a half mile or less along with treacherous travel conditions.

Winter Storm in YANKTON, SOUTH DAKOTA
From 01-DEC-18 07:00:00 to 02-DEC-18 09:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

After a brief period of freezing rain which produced a glaze of light icing during the early morning of December 1, heavy snow occurred for numerous hours. Accumulations over less than a 24-hour period totaled 9.0 inches two miles east of Yankton. Winds gusted to 30 to 35 mph and combined with snowfall to produce several hours of visibility of a half mile or less along with treacherous travel.

Winter Storm in CLAY, SOUTH DAKOTA
From 01-DEC-18 07:00:00 to 02-DEC-18 11:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

After a brief period of freezing rain which produced a glaze of light icing during the early morning of December 1, heavy snow occurred for numerous hours. Accumulations over less than a 24-hour period totaled 7.0 inches at Vermillion and 6.5 inches 6 miles south of Centerville. Winds gusted to 30 to 40 mph and combined with snowfall to produce several hours of visibility of a half mile or less along with treacherous travel.