Unexpained laser like beams over the lake.

This was at a vacation cabin on Spider Lake. The cabin owner came out and asked if we wanted to see the northern lights.  We went down to the lake and saw a pyramid of laser like lights emanating from a vertex 500 to 1000 feet above the lake.  There were six or eight beams of light that had no deflections in them like a flashlight beam has. These were like lasers shining into the water so that the base of the pyramid had to be at least 200 yards across. Each beam was probably 12 to 18 inches in diameter.
We returned to the cabin to finish our pinochle game and no one ever mentioned it again. 
Occasionally I think of the event and wonder what it could have been.  If you have any idea as to what it was I would appreciate an email explaining it.
Source of report indicates that the date of the sighting is approximate.  PD