Driest Autumn of All Time for Many Observers

Legacy of dryness begins at end of July.

Published on: Dec 14, 2011

The Minnesota State Climatology Office has summarized the precipitation deficiencies for September through November, and the numbers are astonishing for many southern counties.

From Goodhue and Dodge Counties in the east to Lincoln and Pipestone Counties in the west, much of the Minnesota landscape is in severe drought as a consequence. The Twin Cities has recorded the driest meteorological autumn in history with just 1.35 inches over September 1st to November 30th. You can read more about this at: www.climate.umn.edu/doc/journal/dry_fall_msp_2011.htm

Others (with their 3-month total precipitation noted in parenthesis) who have reported their driest autumn season are: Lakefield (0.84 inches); Lamberton (0.70 inches); Marshall (0.79 inches); Windom (0.89 inches); Worthington (1.01 inches); Fairmont (1.35 inches); New Ulm (1.32 inches); Owatonna (1.27 inches); Sherburn (0.82 inches); Waseca (1.60 inches); and Hutchinson (1.26 inches). Many others reported one of their driest autumns in history as well. You can see more data and read about this at: www.climate.umn.edu/doc/journal/drought_2011.htm  

The legacy of this dryness goes all the way back to the end of July. Actually a number of observers in southwestern and south-central Minnesota report the driest August through November period as well. Windom, Marshall, and Lamberton have had less than 1.50 inches of precipitation over that 4-month interval.

As a consequence of this dry period, soil moisture storage going into the winter season is extremely low. The Southwestern Research and Outreach Center at Lamberton reported less than 3 inches of stored soil moisture in the top 5 feet earlier in November, and most of this storage was deeper, between 3 and 5 feet. Similarly, at the Southern Research and Outreach Center in Waseca, the early November soil moisture measurements were less than 5 inches in the top 5 feet, most of it in deeper layers. Such conditions predispose the Minnesota landscape to be in drought conditions for the start of next year's growing season, unless there is an early and very wet onset to spring.

-By Mark Seeley, U-M Extension climatologist