Winter Weather — Watonwan, Minnesota

2023-02-15 · Watonwan, Minnesota

Event narrative

Law Enforcement reported that there were no references to whiteout conditions however, multiple vehicles went off the road near Hwy 15 and Hwy 60 in the early morning. One incident included a vehicle rolling onto its side. No reported injuries.

Wider weather episode

A large low-pressure system proceeded across Central and Southern Minnesota. Strong warm air advection provided via southerly flow allowed surface temperatures to create a multi-phased precipitation event.

The environment was abnormally moist for the month of February which set a record precipitable water (0.56 inches) value. Initially, this event began in the form of rain during the daytime hours of Feb 14th. As solar heating decreased through the evening, the rainfall phased into a rain/snow mix and eventually all snow by the morning hours of the 15th. There was a centralized area of heaviest rainfall that occurred in Eastern Minnesota and the St. Croix River Valley. CoCoRaHS observations in areas such as Hennepin County near Plymouth, MN down to Chanhassen MN recorded near 1.2 to 1.3 total inches of rain. Areas in Anoka County such as East Bethel and Ham Lake observed between 1.25 and 1.3 inches of rainfall. In Isanti County near Cambridge, 1.26 inches of rain. The highest observed amount was located in Washington County near Afton, MN with 1.34 inches of rain.

The overall structure of the low-pressure was fairly stacked or in other words vertically aligned. A troughing pattern in the upper-levels was combined with a surface low which in turn supported a tight pressure gradient that could generate strong wind gusts between 40-50+ mph. Numerous airfield stations across Western MN captured strong winds gusts in the early morning hours of Feb 15th between 1 AM to 10 AM. Madison Airport in Lac Qui Parle County observed the strongest recorded gust at 58 mph. Morris AP (Stevens), Redwood Falls AP (Redwood), St. James (Watonwan), and Fairmont (Martin) observed 53 mph gusts. Lastly Benson AP (Swift) and Montevideo AP (Chippewa) observed just above 50 mph gusts. No wind damage was reported from any of these observations.

As a result of increased wind speeds and precipitation phasing to all snow, blowing snow became a factor in Western Minnesota. Specifically, county law enforcement or emergency management in Stevens, Swift, Chippewa, Lac Qui Parle, Yellow Medicine, and Douglas counties all reported receiving numerous calls for motorists stuck in ditches. They also reported the visibility was very poor, there were sporadic snow drifts on roadways making travel impossible.

For the extreme Western Minnesota in terms of snowfall accumulations, CoCoRaHS observations recorded 2.2 inches northwest of Morris, MN (Stevens). The remainder of nearby observations sites recorded amounts between 1-2 inches of snow.

Source: NOAA Storm Events Database, event_id 1076759. Narrative written by the NWS forecast office that issued the report.