Tuesday, December 27, 2011

Top 5 Minnesota weather events of 2011

As 2011 wraps up, it was another historic year in weather filled with extremes.  Some of the year’s events include tornado outbreaks across the southern United States, and closer to home, a top five snowfall for the 2010-11 season, humid summer, highest peak wind gust recorded in state history, a tornado in Minneapolis, and record fall drought.  In reflection on 2011, here are my top 5 weather events for the year.  The top events as voted on by the Minnesota Climatology Working Group are here.

#5 Minneapolis tornado

Note: While this event was listed number one by Minnesota Climatology Working Group, this list presented here was weighted on the significance of unusual events that are often historic.  While this tornado impacted a lot of people in a populated area, the damage was relatively minor compared to tornado outbreaks across the central and southern United States during the spring.

The second tornado to hit Minneapolis in three years occurred on May 22th, and would be later classified by the National Weather Service in Chanhassen as a high-end EF-1. The tornado killed one person and injured 48 while it was on the ground for 14.25 miles from St. Louis Park to Blaine. The heaviest concentration of damage was confined to north Minneapolis.  The majority of the damage was downed trees atop buildings and vehicles, however the twister did demolish garages, sheds, and rooftops at during peak strength.

The supercell that produced the twister was part of a larger storm extending from northeastern Oklahoma, and through the Mississippi Valley to northern Wisconsin. There were 56 reports of tornadoes across the United States this day with the strongest one affecting Joplin, Missouri. 162 people lost their lives, and thousands were displaced from their homes as large sections of the city were leveled.

Additional reading:

#4 Humid summer

319 hours of dew point temperatures of 70 degrees or higher was recorded at the Twin Cities International Airport this summer, and a record was set for dew point temperatures of 75 degrees or higher with 103 hours.  On July 19th, 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 this day 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.

Shortly after 7 PM on July 19th, I recorded a heat index reading of nearly 118°F at my home in Shakopee.  Temperatures were into the 90s, with dew points hovering around 80 degrees.


#3 Record wind speed in Donaldson

The first day of September and the meteorological autumn season brought severe thunderstorm winds across northwestern Minnesota as temperatures climbed into the 90s with dew points into the 70s.  An automated station a mile west of Donaldson in Kittson County recorded a wind gust of 121 MPH during the early morning hours.  This measurement was substantiated by damages inflicted in the surrounding landscape by such strong winds.  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.  The National Weather Service, Minnesota State Climatology Office, and National Climatic Data Center tested the data collected from this station and later confirmed 121 MPH reading - the strongest wind speed ever measured in Minnesota.  The old state record wind speed was 117 MPH from a thunderstorm near Alexandria, MN back on July 19, 1983.  While wind speeds of this magnitude, and higher have likely occurred in Minnesota in the past, there was not any instrumentation that survived to record the wind speed.  According to Dr. Mark Seeley, the wind in Donaldson was measured by an R.M. Young Wind Monitor (aero vane), a mechanical, propeller type instrument. The actual instrument is said to have a measurement range up to 224 MPH.

#2 Record fall drought

1.36 inches of liquid precipitation fell from September 1 to November 30 in the Twin Cities, which made it the driest autumn since records began in 1871.  The entire state saw below normal precipitation for the season.  On a larger scale, the lack of rain during the fall continued the ongoing drought across much of Minnesota since late summer.  Sections of southern and western Minnesota are depicted by the U.S. Drought Monitor as falling in “moderate” to “severe” drought categories.


#1 Fourth snowiest snow season on record

The top event of the year goes to snow.  The snowy trend carried into 2011 from December 2010 as we saw roughly the same amount of snow in the Twin Cities during the first four months of this year as we did in November and December of the previous year. 


By the time the snow ended for the season, MSP recorded the fourth highest total on record with 86.6 inches.


February snows on the 20th and 21st shattered more climatological records.  We witnessed the largest single snowstorm for the month in the Twin Cities since 1891 with an official total of 13.8 inches. A foot was recorded at my home in Shakopee, and I put together a time lapse of the snow as it feel in the backyard.

Along with the top five list, here are my storm chasing highlights from the year.  Across Minnesota, it was a quiet year compared to 2010 with fewer ideal setups for severe storm initiation.  As a result, fewer tornadoes were reported in 2011 (31) than the 30-year historical average (37).  There seemed to be one ingredient missing or interference of mesoscale dynamics in these setups that prohibited storms from being really explosive this year.

Do you agree with my rankings?  How would you rank the top five events from Minnesota?  Share your thoughts below.  I would also like to thank everyone that stopped by this site this year.  Hopefully you learned a little bit about the weather this year, and look forward to your support in 2012!


1 comment:

  1. Ryan: sorry I don't have another way of contacting you, so I hope you don't mind if I list my top five here and compare them to yours. We are actually pretty close from what I can tell. Notice that I almost always choose a event that could have happened but didn't for honor mention, after all mother nature can unleash her wrath, or hold it back. This was posted in the comment section of Paul Huttner's blog dated Dec 22nd.

    "My top five weather events for 2011. First let me explain how I judge them. #1 was it a record event, #2 how many people did it affect and did it change a large number of people's daily routine, #3 economic impact on the state's economy.

    #1 Hands down I agree with you, the winter of 2010/2011 (after all you can't include that in 2010, most of it didn't happen yet lol)

    # 2 Record dew points set in Mn on July 19 at Morehead MN 88°, and a record in Minneapolis of 82°
    ( impacts felt almost state wide)

    #3 Drought....Driest autumn on record. ( again impacts felt almost state wide)

    #4 Record Feb single snowfall total for Mpls of 13.8" (many areas had more)

    #5 Minneapolis Tornado. (while catastrophic and painful for those in it's path, it was very much a local event.But I can understand those that have it number 1)

    I always try and reserve the honorable mention to a weather story that wasn't. In 2010 it was the lack of tornadoes in the metro in spite of a record shattering year state wide.

    So this years honorable mention goes to the flood that wasn't. After one of the snowiest years on record and despite the doom and gloom of local forecasters, mother nature decided to cooperate with a slow spring time melt....(I know...tell that to the folks south of here, their pain was immense)