From the Lawrence Daily Journal-World for April 18, 1971:

Kansas Power and Light linemen were looking at a full day of work at the Sixth Street KPL substation after a curious squirrel sparked a blackout in the downtown area. The squirrel, having apparently entered the area by walking along a 12,000 volt power line, had caused a minor flash fire which led to a 1-hour 12-minute power outage covering the area from Sixth to 11th along Massachusetts, Vermont, and New Hampshire. An additional three-block-wide area along 11th Street from Mass to West Campus Road was also affected. In the post office at 11th and Vermont, workers could not see in the windowless work area and were unable to sort mail, resulting in a two-hour delay in mail delivery to some sections of the city. Police also felt the impact of the power outage as virtually every fire and burglar alarm at banks and businesses was tripped.