We knew it was coming, and today the Twin Cities NWS made it official.
Minnesota set a new record for the highest number of tornadoes this year. Here are the numbers:
104 tornadoes in 2010 (4 EF4, 4EF3, 8 EF2, 30 EF1, 58 EF0)
Previous record: 74 tornadoes in 2001
46 injuries (all but one occurred on June 17th)
Longest: 39.6 mile path length (Douglas and Otter Tail counties). EF4 rating, 1/2 mile wide. On the ground for 1 hour & 2 minutes!
Wadena tornado: EF4 rating. 10 mile path length. 17 minutes, 20 injuries.
It is quite remarkable (and fortunate) that none of the 104 tornadoes in Minnesota in 2010 touched down in Hennepin, Ramsey or Anoka counties. Thus the most densely populated core of the Twin Cities metro escaped 2010 without a tornado touchdown during the most active tornado year in Minnesota history.
NOAA SPC preliminary 2010 tornado count for Minnesota.
Imagine the devastation today from an outbreak similar to the incredible 1965 Twin Cities outbreak.
According to preliminary SPC reports Texas has posted 105 preliminary tornado reports so far in 2010. IT is almost certain that number will drop (possibly by a third) once final reports are issued at year's end. Thus, barring a major increase in the Texas numbers in the next 60 days, it is likely that Minnesota will lead the nation in observed tornadoes for the first time on record.
Is tornado alley shifting north?
There is no doubt that the epicenter of tornado alley shifted about 500 miles north in 2010.
The bigger question on the mind of many meteorologists and climatologists is whether these numbers signify a trend towards a northward shift in tornado alley. Or is 2010 just a blip in the longer term data.
I took a look at the numbers for tornadoes by decade in Minnesota and Oklahoma. It's not really an apples to apples comparison since Minnesota is slightly larger than Oklahoma, but it does show some interesting (and perhaps valid) trends.
You can see on the graph below that Minnesota's (bottom line) overall tornado numbers have been climbing, and Oklahoma's (top line) numbers have fallen sharply during the past decade.
The two lines crossed for the first time in 2010. Minnesota's 104 tornadoes is likely to exceed Oklahoma's still preliminary number of 73 by a large margin at year's end.
It is alarming to note that the average annual number of tornadoes in Minnesota has nearly doubled from 25.8 to 48.4 in the past 11 years when compared with the longer term averages since 1950!
With the annual average number of tornadoes in Minnesota at 48 per in the past 11 years, and the top two tornado years on record having occurred in the past 10 years, it will be interesting to see if the trend towards increased tornado numbers in Minnesota holds in the coming decade.
If this is the new normal, we may need to start thinking of Minnesota as "tornado alley north."