Created: 02/20/2009 9:52 PM KSTP.com | Print Story By: Dave Dahl

Volcanoes in Minnesota?  Believe it or not, they've played a part in our weather and it'll probably happen again!

Volcanoes produce lava and ash.  Most of the rocks on the North Shore of Lake Superior were created by cooling lava.  Much of southeastern Minnesota contains bentonite clay, which is formed by volcanic ash.  This of course happened many thousands if not millions of years ago, but even today volcanoes are playing a part in our life here in Minnesota.

One of the most recent volcanoes to affect the weather here in Minnesota was the eruption of Mt. Pinatubo in the Philippines back on June 15th, 1991.  How can something that far away affect our weather here?  Easily!  The ash plume reached 21 miles high and 250 miles wide during the 2 hour-long eruption.  It was the largest disturbance in the stratosphere since the eruption of Krakatau in 1883!  The aerosol cloud took only 2 weeks to spread completely around the globe and covering Minnesota as well.  

This cloud over the earth reduced global temperatures in the northern hemisphere by as much as .5 to .6 degrees Celsius and the entire planet was cooled by .4 to .5 degrees Celsius.  It's possible that this cooling was responsible for the unusually cool fall in 1991 in the Upper Midwest that lead to the record snowfall in Minnesota and in the Twin Cities, which was 28.4 inches during the Halloween Blizzard.  The United States also experienced its third coolest and third wettest summer in 77 years during 1992.  In the 3 summers that followed the eruption, we only had a total of 7 days when the temperature exceeded 90 degrees here in the Twin Cities, and our average is 15 days every summer.  Another possible effect was the flooding along the Mississippi River in 1993. 

When clouds of gas and ash from volcanoes travel around the globe and happen to pass over Minnesota, we get the benefit of some spectacular sunrises and sunsets.  The hews of red and orange are nothing short of remarkable.  The next volcano to affect us here in Minnesota may not be that far off.  Recent seismic activity around Mt. Redoubt in Alaska along with steam and volcanic gases coming from its peak may mean an eruption is immanent.