A monthly electronic newsletter summarizing Minnesota's climate conditions and the resulting impact on water resources. Distributed on the first Thursday of the month.
State Climatology Office - DNR Division of Ecological and Water Resources, St. Paul
distributed: January 8, 2022
What happened in December 2021:
- December 2021 continued the wet spell that began in late August. The preliminary average statewide precipitation total was 1.79 inches or .71 inches above normal. The wettest locations were in the northeast, where a location seven miles northwest of Two Harbors had 4.43 inches, or 2.46 inches above normal. Most places in northeast Minnesota were from one to two inches above normal. The driest locations were along the border with Iowa, where precipitation was close to slightly below normal. For 2021, the Twin Cities finished with 25.96 inches of precipitation or 5.66 inches short of normal. Duluth had 25.71 inches or 5.47 inches short of normal. For most locations, 2021 was the second year in a row of below normal precipitation.
[see: December 2021 Preliminary Precipitation Total Map | December 2021 Precipitation Departure Map | December 2021 Climate Summary Table]
- December 2021 was an active month weather-wise and had four events that stood out for the month.
- The first large winter storm of the 2021-22 snow season dropped a swath of six to twelve inches of snow across much of northern Minnesota, with higher amounts along the north shore. Inland from Superior near Grand Marias, a snow total of 20 inches was reported. Bitterly cold wind-chill temperatures followed. Between Saturday evening the 4th and 11 AM Sunday the 5th, over two hundred auto crashes were reported by MNDOT.
[see: First Major Winter Storm, December 4-6, 2021]
- December 10-11, 2021, was the next event, this time dropping heavy snow over southern Minnesota. The snow reached peak intensity between 3 and 9 PM on the 10th, with snowfall rates approaching two inches per hour at times. The MSP airport received a healthy 11.8 inches from the storm, but was only a few miles north and west of the highest totals in the state. On the north side of town, amounts struggled to reach six inches. Snowfall totals of six inches or more covered roughly the southeastern 1/3 of the state. The highest accumulations, generally in the range of 12 to 18 inches, stretched from Sibley and Le Sueur Counties, into the southeastern half of the Twin Cities. There was a foot of snow on the ground in the Twin Cities, but it would not last.
[see: Southern Minnesota Winter Storm, December 10-11, 2021]
- Most of the time, the heavy snow of the 10th-11th would have been the biggest weather story of the month. But December 2021 was not your typical December. On December 15th warm muggy air surged into the state, with conditions ripe for severe storms and tornadoes. A swarm of tornadoes struck south central and southeast Minnesota with a preliminary total of twenty. Hardest hit was Hartland in Freeborn County where an EF2 ranked tornado damaged buildings in downtown. In the derecho that swept across southern Minnesota, high winds up to 75 miles per hour were reported. Tragically, a man was killed in Rochester when a tree fell on him.
[see: Mid-December Tornadoes, Derecho, and Damaging Cold Front--December 15-16, 2021 ]
- Another heavy snow-producer blasted central and northern Minnesota, making it the third time this December that some part of Minnesota received over a foot of snow. The total snowfall increased from south to north across the state, reaching maximum values near Brainerd and Hinckley, and also in the higher terrain near Lake Superior. A spotter near St Mathias reported 18 inches, and observers along Highway 210 from Motley and Pillager, through Baxter and Brainerd, to Riverton and Crosby consistently reported 13 to 16 inches. 12 to 14 inches was reported in and around Hinckley, Pine City, Beroun, and Finlayson.
[see: Another Large Winter Storm, December 26-27, 2021]
- For fourth December in a row, statewide average temperatures wound up being above normal. December 2021 was also the coldest December since 2017, despite having an average temperature of 20.3 degrees or 2.3 degrees above normal. On December 15, many locations saw high temperatures in the 50s in the central parts of the state and 60s in the south. The Twin Cities had a record high temperature of 58 degrees on the 15th. The warmest reading of the month was 66 degrees at Caledonia on the 16th (note: due to the observation time the 66 degrees was on the 15th). The coldest reading of the month was -35 on December 29th was at Warren in Marshall County in northwest Minnesota.
[see: December 2021 Climate Summary Table ]
Where we stand now:
- After the mid-December warmth put a dent in the snowpack across the state, the second half of the month brought snows and colder air. The snowy pattern continued for the first week of January, especially in the north. On January 6, there is a wide range of snow cover conditions in Minnesota, ranging from bare ground in the southwest, to 4-6 inches on the ground in the Twin Cities Metro, 6-12 inches in the central parts of the state, and a foot or more on the ground in the north central and northeast. The deepest snowpack is found along the north shore in Lake and Cook County with depths of 15-24 inches.
[see: Weekly Snow Depth and Ranking Maps | NWS Snow Depth Estimation Map | Midwest Regional Climate Center Snow Depth Map]
- The drought that began in 2020, is persisting into 2022, but conditions have improved from the peak in mid-August 2021. The U. S. Drought Monitor map released on January 6, 2022 depicts 30% of the state free of drought designation. About 31% of the state was Abnormally Dry, and 29% of the state in Moderate Drought conditions. Portions of north central and northeast Minnesota are in Severe Drought conditions. The U.S. Drought Monitor index is a blend of science and subjectivity where drought categories (Moderate, Severe, etc.) are based on several indicators.
[see: Drought Conditions Overview]
- The U.S. Geological Survey reports that stream discharge values in Minnesota (where winter measurements are possible) are above historical medians for the date in the south, central and the Red River Valley and below the historical median in the northeast. Most rivers and streams are now impacted by ice.
[see: USGS Stream Flow Conditions]
- In general, falling lake levels in 2021 stabilized by the autumn but many are still lower than in recent years. The level of Mille Lacs was below the median for early January 2022 and has been below the median since June 2021. The level on Lake Minnetonka on December 6 was 928.0 feet, about half a foot lower than one year ago. The Grays Bay Dam has been closed since July 21, 2021. White Bear Lake was at 923.29 feet on January 7, about .87 feet lower than one year ago. The reading may be affected by ice. The level of Rainy Lake improved in the late fall and is in the median range. The level of Lake of the Woods continues to rise as well and at the start of 2022 is just reached the lower end of the median range. Lake Superior was at 601.35 feet on December 31, a foot lower than the monthly average for late December.
[see: Mille Lacs Lake Water Level | Lake Minnetonka Water Level | White Bear Lake Water Level | Lake of the Woods Control Board Basin Data | Corps of Engineers Great Lakes Water Levels]
- On November 29, 2021 the Agricultural Statistics Service reported that topsoil moisture across Minnesota was 2 percent Very Short, 11 percent Short, 80 percent Adequate, and 7 percent Surplus. Corn for grain harvest was 97% completed by November 14. Five days ahead of 2020 and fifteen days ahead of the five year average. Soil moisture levels at Lamberton on November 15 had fully recovered from the drought and are showing about a two inch surplus.
[see: Agricultural Statistics Service Crop Progress and Condition | U. of M. Southwest Research & Outreach Center (Lamberton) | U. of M. Southern Research & Outreach Center (Waseca)]
- The potential for wildfires is currently rated by DNR Forestry as Low across Minnesota.
[see: Fire Danger Rating Map]
- Soil frost depths under sod are fairly shallow for early January, ranging from a about one foot or less at Minnesota observing locations in the south and central to sixteen inches at Duluth and 21 inches at Grand Forks. With the colder air in place in early January, the frost depth is deepening.
[see: National Weather Service Frost Depth Data | MnDOT Road Frost Depths | University of Minnesota - St. Paul Campus Soil Temperatures Under Sod]
- Like many lake ice-in seasons, the ice formed in fits and starts across the state. Lakes that froze over in November across central and southern Minnesota generally re-opened in December. Far northern lakes tended to stay ice covered in the December thaw, but was not universal. One of the last lakes to freeze over was Grindstone Lake in Pine County on December 23.
[see: DNR Conservation Officer Reports | 2021 Ice-In Dates] | Median Lake Ice-In Dates]
- The January precipitation outlook has a tendency for above normal precipitation in Cook County, but equal chances for below, normal and above normal precipitation over the rest of the state. January precipitation normals range from near one-half inch of liquid equivalent in western Minnesota to just over one inch liquid in eastern sections of the state. The median snow cover at the end of January ranges from near five inches in southwest Minnesota, to over 15 inches on the ground in northeastern Minnesota (greater than 24 inches along the Lake Superior highlands).
[see: Climate Prediction Center 30-day Outlook | January Precipitation Normal Map]
- The January temperature outlook is heavily weighted for below normal temperatures, especially in the northwest. Historically, January is Minnesota's coldest month. Normal January high temperatures range the low-teens in the north, to near 20 in the south. Normal January lows range from near minus 10 degrees in the far north, to the single digits above zero in southern Minnesota.
[see: Climate Prediction Center 30-day Outlook | Temperature Normals]
- The 90-day precipitation outlook for January through March indicates an equal chance for below normal, normal and above normal temperatures for the state. There is a tendency for above normal precipitation for the far southeast part of state, with the rest of the state having equal chances for below normal and above normal precipitation.
[see: Climate Prediction Center 90-day Outlook]
- The National Weather Service produces long-range probabilistic river stage and discharge outlooks for the Red River, Minnesota River, and Mississippi River basins. These products address both high flow and low flow probabilities.
[see: National Weather Service - North Central River Forecast Center]
From the author:
- What lies in store in 2022 with regards to the drought? The severity has lessened a bit due to the wet fall and early winter. There is still moderate and severe drought in the northeast, due to two years of below normal precipitation. Large lakes in the northeast (Vermilion and Sea Gull) froze over in early November at levels still quite low. A very snowy season will give an assist, but it will be when the rains come back in April and May will that determine the direction of the drought. The Climate Prediction Center's outlook for April-June does have a tendency for above normal precipitation in eastern Minnesota, but we will have to wait and see.
Upcoming dates of note:
- January 20: National Weather Service releases 30/90 day temperature and precipitation outlooks
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Pete Boulay, DNR Climatologist