Here are candidates for the top five weather events of 2011 from the Minnesota State Climatology Office.
The coldest air mass to hit Minnesota in two years sideswiped the state on January 20-21, 2011. The coldest air temperature found on January 21 was -46 at International Falls. This was the coldest temperature at the "Icebox of the Nation" since -46 on January 6, 1968. The temperature also bottomed out at -46 at Babbitt as well. This was the coldest air to move over Minnesota since January 14, 2009 when Babbitt saw -48. This cold came in the middle of one of the snowier winters in recent years.
On September 1, severe thunderstorm winds were clocked at 121 mph at an automated station a mile west of Donaldson in Kittson County. Two large commercial grade steel bins were torn out from the local grain elevator and the significant tree damage in the area matched winds of that extreme range. 121 miles per hour is the strongest wind speed measured in Minnesota. While wind speeds of this magnitude, and higher have likely occurred in Minnesota in the past, there wasn’t any instrumentation that survived to record the wind speed. Due to the proliferation of automated weather stations in Minnesota, there is a greater chance that one of these gusts can be measured.
A scant 1.36 inches fell from September 1 to November 30 in the Twin Cities, the driest since modern records began in 1871. The dryness in the Twin Cities was a reflection of the large scale drought situation that intensified across Minnesota in the late summer and autumn. Soil moisture levels at the University of Minnesota Southern Research and Outreach Center in Waseca by mid November were the lowest seen in recent years.
On Tuesday, July 19, 2011 the dew point temperature reached 82 degrees at the Twin Cities, breaking the old record of 81 that was set on July 30, 1999. In addition, the highest dew point temperature recorded in Minnesota was set at the Moorhead Airport with 88 degrees, breaking the old record of 86 that was set at both Pipestone and St. James on July 23, 2005. The high dew point temperatures had some odd effects. When people wearing glasses walked outside from the indoor air conditioning, their eyeglasses instantly fogged up. Window air conditioners quickly sold out around the Twin Cities.
Minneapolis Tornado: Sunday, May 22, 2011. The Minneapolis tornado killed one person and injured 48. The hardest hit area was from Lowry Avenue and Logan Avenue in Minneapolis to 42nd and Lyndale Avenue. The tornado then crossed the Mississippi River and caused damage in Anoka County. This is the second tornado to hit Minneapolis in three years. There hasn’t been a tornado reported in Ramsey County since 1998.
Honorable Mention #1 Brown Christmas 2011
Similar to 2006 when most places south of Highway 2 from Grand Forks to Duluth had little or no snow on the ground. In 2011 the snow-free area looks to be even more extensive with northwestern Minnesota also most likely not having any snow on the ground on Christmas Day.
Honorable Mention #2 Flooding on the Minnesota and the Red River.
A wet autumn in 2010, along with a snowy winter caused around round of flooding on the Red River and the Minnesota River. The Red River of the North at Fargo was above flood stage for 150 days, finally falling below flood stage on August 27.