Waves in the sky

This is one of the first photos I made the other night as the waves of aurora began to wash over the skies of northeast Minnesota.  The aurora forecast and cloud forecast were good so I left home just before 11:30 PM and arrived at McFarland Lake just after midnight.  I've been wanting to catch a good aurora show at McFarland for some time now.  After several attempts over the last year I finally got what I was hoping for.  This lake has a public swimming beach on the south shore and the beach looks almost due north, perfect for viewing the northern lights!  The lake also has very distinctive bluffs lining its shores which makes for a very photogenic horizon.  The aurora was already active when I left home, but the lights were faint at first.  I was hoping to get to McFarland just after midnight as the lights often flare up in their intensity around that time.  Sure enough, as I was driving up the Arrowhead Trail and midnight drew near, the lights started to pick up in their intensity.  When I arrived at the lake there was a full-blown aurora storm waving and dancing throughout the sky.  I scrambled to get my gear set up and as quickly as I could started making images.  For the next 45 minutes I stood in awe as the sky erupted with waves of light and color over and over again.  In this picture you can see a line of aurora that "points" to the left.  This line resembled the wall cloud of a quickly advancing thunderstorm and much like a thunderstorm, the line quickly moved from right to left across the sky then faded away.  And this was just the beginning of what would end up being an awesome geomagnetic storm that would carry on through the rest of the night and well into the morning.