Year End Summary for 2020
YEAR END SUMMARY STATION NAME: Little Cannon River nr Cannon Falls, CR24 STATION NUMBER: H39016001 YEAR: 2020 PREPARED BY: Fred Bowen, fred.bowen@state.mn.us CLIMATE SUMMARY: Division 9, 2020: Mild conditions and near-normal snowfall January through into April topped off a moderately snowy early winter, leading to normal to slightly above-normal seasonal snowfall totals of 35-55 inches. The May-September growing season was warm and slightly wet, punctuated by very warm June through August conditions, and occasional bouts of heavy rainfall. A widespread heavy rainfall event on June 28-29 produced 4-6 inches near the Cannon and Vermillion rivers, with other 2-4-inch rains falling on May 17 and June 10. Temperatures fell below freezing in early October, but with little precipitation falling, the liquid precipitation season extended to October 15. Snow fell occasionally from mid-October into early November, with most of the area seeing totals of 4-8 inches by the end of November. Extreme warmth melted much of the snow during early-mid November, and the rest was melted by persistently mild conditions during the remainder of the month. No snow was on the ground as of December 1. STATION OPERATION SUMMARY: Is this site monitored year round? No Open water dates - estimated Ice out and Ice in: Ice out 3/8/2020, Ice in 12/1/2020 Open water sites ONLY. Period of data record (if different from ice out/ice in dates): 3/8/2020 - 11/1/2020 Summary of equipment - related factors that impacted data collection: Station was down from 5/25/2020 - 6/10/2020 with no data being logged or transmitted. This period was estimated in daily Qs. DISCHARGE SUMMARY: Number of flow measurements for monitoring season: 3 Was the full range of flows measured for the season? NO, highest calculated discharge = 1390 cfs, highest measured discharge = 179 cfs, 13% of highest calculated discharge Was a new rating developed? YES. Created Rating 9.0. Low flows over the last couple years were showing scour. Adjusted rating below 540 cfs to account for this trend. Used 3/3/2021 msmnt to define low end and changed log offset to 6.95 ft. General summary of control changes/shifts needed: Deposition shift applied end of July through the end of the year based on the 9/2/2020 measurment. Quality of computed daily discharges: Estimated due to COVID and a regression to estimate the discharges during equipment issues. The rest are mostly good and fair due to rating quality. PRECIPITATION DATA OVERVIEW: Was precipitation data collected at this site? YES Climatological liquid precipitation period: 4/16/2020 - 10/16/2020 Was there a complete and acceptable precipitation record for this period? NO, station data between 5/25 - 6/10 was non-existent and missed a large event. DISCLAIMER: In the spring and summer of 2020, field work was limited due to the COVID 19 related travel and work restrictions. Because of this, there are less frequent discharge measurements, which can lead to more uncertainty and data estimation. This is reflected in the quality codes of the discharge data.