Sunday, December 26, 2010

2010: A Year in Review

Anyone who says that Minnesota or Wisconsin are boring must not have been living here in 2010. After what was a somewhat slow start to the year, things picked up dramatically and really haven't let up since late spring. To mark the end of the year, I decided to take a look back at the year, and rank what I think are the top 5 weather events of the year. I first thought of doing a top 10, but really a top 5 I think is more reasonable. So without further delay, my top 5.


Number 5 - Snowless March

While the other top events of 2010 will consist of weather actually occurring, this one was chosen due to the lack of weather. For the first time since weather data has been recorded, no measurable snow was recorded at the MSP airport, or at Eau Claire's airport. While some may not think this is much of a surprise due to it being March, and almost spring, it actually is a surprise because March is typically one of, if not the snowiest months that we see. This rare event, however, did help reduce the amount of flooding that is typically seen every year due to the snow melt into the Wisconsin and Minnesota rivers.

Number 4 - Record Low Pressure/Windstorm




On October 26, 2010, a low pressure system, with a cold front attached moved across the northern United States, while a secondary low moved up from the south and merged into one "megalow". The low moving from the south ended up becoming the main low, and rapidly deepened (or strengthened) bringing some incredibly strong winds along with it. The main low bottomed out around 28.20 inches of mercury (954.96mb) at Bigfork in Itasca County. This shatters the old Minnesota lowest pressure record of 28.43 that was set in the November 10, 1998 storm at both Austin and Albert Lea. The state of Wisconsin also broke their state record for pressure, with Superior recording a reading of 28.39 inches of mercury (961.3mb). That broke a record that stood for more than 28 years, dating back to April 3rd, 1982. The measurement was taken in Green Bay. The storm brought sustained winds between 20 and 30mph, with gusts of 40-60+mph. This caused power outages, trees to fall, and people's lawn furniture to end up in their neighbors yard. This low was also able to tap into some moisture from the south, and cold air from the north, creating the first decent snowfall across Minnesota and North Dakota. Blizzard warnings, High Wind warnings, and a whole slew of other advisories cover the area. The cold front extending from the low ended up causing problems across a good portion of the central and eastern United States.

Number 3 - Southern Minnesota/Western Wisconsin flooding

Beginning the afternoon/evening of September 22nd, a moist airmass moved into the area, and a slow moving warm front moved into southern Minnesota before stalling out to a stationary front. The combination of these two things created a long duration heavy rain event which ended up causing rivers to overflow, and farm fields to turn into lakes. The rain didn't stop falling until late in the day on September 23rd, but its effects were felt days, even weeks later. Below is a graphic of rain totals that were observed across southern Minnesota and western/southern Wisconsin, courtesy the National Weather Service in La Crosse, WI.



All of this rain, along with its eventual runoff, caused flooding for a couple weeks after the rain had ended. Fortunately, this rain was followed by a dry stretch that lasted nearly a month. This allowed the rivers to eventually fall below flood stage, fields to dry out, and farmers to make good progress on their annual harvest.

Number 2 - June tornadoes/record season

There was much thought put into whether or not to put this at number 1 or 2, and in reality, it could easily be put in the number 1 spot. But after all that thinking, the record year Minnesota had takes the number 2 spot. While the season as a whole was quite remarkable, one day in June covers a good chunk of the overall tornadoes that Minnesota saw through the year. A warm and extremely unstable airmass moved into Minnesota during the day of June 17th, 2010, setting up what would be the largest outbreak of tornadoes Minnesota would see during a 24 hour period. Three fatalities (2 from northwest Minnesota, and 1 from south central MN), as well as many injuries were reported as a result of the outbreak. 48 of Minnesota's record breaking 105 tornadoes were reported on the 17th of June. Although a majority of the tornadoes were rated EF-2 or lower, four of them received EF-3 ratings, and three of them received EF-4 ratings. Below is a storm reports map from the 17th.



Also, here is a link which contains info of each tornado for Minnesota. http://www.crh.noaa.gov/images/mpx/2010torlist.pdf

Number 1 - Blizzard of 2010

This years number one event actually happened closer to the end of the year. On December 11th, 2010, a large, slow moving area of low pressure moved across central IA and northern IL, strengthening and tapping into Gulf moisture as it trekked east. North of the low, a wide swath of snow formed, dropping snow at rates of 1+ inches/hour. Wind speeds increased as the low strengthened, creating whiteout conditions and making travel impossible. Many roads were considered impassible, and access to the I-94 was restricted across western Wisconsin due to those whiteout conditions, and large snow drifts that were forming on the road. What makes this storm such an impressive system is the fact that such a large area saw well over a foot of snow, and even those areas that initially saw a little mixing of freezing rain and sleet still saw 10+ inches of snow. Below is the snowfall map from that storm, over a 24 hour time frame, courtesy of the National Weather Service.



Although there were a lot of high totals of snow, some notable ones were from Osceola, WI with 23 inches of snow, Eau Claire, WI with 22 inches, and even the Twin Cities with 17 inches. In fact at the Metrodome in Minneapolis, the snow was so much that it caused the roof of the dome to collapse, forcing a game between the Vikings and the Giants to be moved to Detroit while repairs were done. Schools in Minnesota were closed for several days after because the snow removal process was slow going, and rightfully so. That storm, as well as several others in the Twin Cities, led to a record breaking December for snow totals on record. Here in Eau Claire, we are second snowiest on record at this point, but are less than 2 inches away from surpassing the top mark for the month of December. With at least 3 months of potential snow accumulating days it will be interesting to see how much actually falls over the winter, and how much of an impact it will have on the annual spring floods that we see. 2010 will be tough to beat when it comes to significant weather, but 2011 may be full of a few new surprises. You never know :)