Broad warm advection developed early on December 29 as a strong trough aloft sheared northeast through the central and northern Plains. A period of strong frontogenesis shifted northeast, accompanied by a deep dendritic layer which produced snowfall rates up to an inch per hour.
Every event with a place to put it; 24 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS FSD wrote it up.
Broad warm advection developed early on December 29 as a strong trough aloft sheared northeast through the central and northern Plains. A period of strong frontogenesis shifted northeast, accompanied by a deep dendritic layer which produced snowfall rates up to an inch per hour.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Sioux Falls, SD wrote its last area forecast discussion before the first event at Dec 28, 10:57 PM CST, 4 hours 3 minutes earlier.
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</html>The national radar mosaic for the moment the first event began.
19 winter weather, 5 winter storm. Local standard time, as filed.
Moderate to briefly heavy snowfall at times totaled 6.8 inches 4 miles south southwest of Pickstown, 6.5 inches 11 miles south southeast of Burke and 6.0 inches at Gregory.
Moderate to briefly heavy snowfall at times totaled 6.0 inches 2 miles north of Lake Andes and 4.5 inches at Platte.
Snowfall totaled 4.3 inches at Chamberlain and 3.0 inches 2 miles south of Pukwana.
Moderate to briefly heavy snowfall at times totaled 6.0 inches 5 miles west of Armour.
Moderate to briefly heavy snowfall at times totaled 6.0 inches at Tyndall.
Snowfall totaled 4.2 inches 4 miles southwest of Stickney and 2.8 inches at White Lake.
Snowfall totaled 4.0 inches at Wessington Springs.
Moderate to briefly heavy snowfall at times totaled 6.0 inches 1 miles west southwest of Yankton.
Snowfall totaled 5.0 inches at Mitchell.
Snowfall totaled 5.5 inches at Menno and 5.0 inches at Parkston.
Snowfall totaled 5.5 inches at Vermillion and 4.0 inches 6 miles southeast of Centerville.
Snowfall totaled 3.5 inches at Alexandria.
Snowfall totaled 5.3 inches at Woonsocket.
Snowfall totaled 3.0 inches at Huron.
Snowfall totaled 5.0 inches 6 miles north northeast of Elk Point and 4.5 inches in North Sioux City.
Snowfall totaled 5.0 inches at Marion, 4.5 inches at Hurley and 3.8 inches at Parker.
Snowfall totaled 5.0 inches at Bridgewater and 3.0 inches 6 miles northwest of Montrose and 5 miles northeast of Salem.
Snowfall totaled 4.0 inches at De Smet and 3.0 inches at Iroquois.
Snowfall totaled 4.3 inches at Howard.
Snowfall totaled 4.0 inches at Canton and 3.9 inches 1 mile north northeast of Harrisburg.
Snowfall varied from 3.5 to 5.0 inches around the Sioux Falls area, and 4.0 inches at Colton.
Snowfall totaled 4.9 inches at Flandreau.
Snowfall totaled 3.6 inches 2 miles north of Chester and 3.3 inches at Madison.
Snowfall totaled 3.1 inches at Brookings and 3.0 inches at White.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in South Dakota in 2020Every state in 2020This day in weather historyWarnings in South Dakota, December 2020
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-10-01. Each event’s entry at NCEI: 934600, 934601, 934605, 934602, 934603, 934606, 934621, 934604, 934607, 934608, 934609, 934619, 934623, 934624, 934611, 934613, 934616, 934625, 934630, 934612, 934614, 934629, 934631, 934628.