Winter Storm — Minnehaha, South Dakota

2020-11-10 · Minnehaha, South Dakota

Event narrative

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.

Wider weather episode

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.

Source: NOAA Storm Events Database, event_id 928921. Narrative written by the NWS forecast office that issued the report.