Beams emitted from two crafts

While camping on the Santa Maria River in the spring of 2008, my friend and I looked out the tent and saw beams being emitted in a lateral fashion approximately 900-1,500 feet above the valley floor. Initially the beam was emitted from one craft, towards the other craft (that we did not know was there yet). The initial beam was a neon blue hue, the beam traveled in what seemed to be slow motion, and only for a couple of hundred feet before dissipating. A second craft then emitted a beam back towards the first craft with a neon green beam in the same way.
There was no sound emitted from the crafts, and they seemed to be hovering in place. The crafts had a few exchanges of beams in this way, and then disappeared without further consequence. My tent mate rolled to me, asked if I saw that, I responded that I did and then we rolled over and went to sleep dumbfounded and a bit terrified. The crafts were never visible, just the beams were visible.
At the time of the sighting, my friend and I had just graduated college with environmental degrees. We were not under the influence of any substances. There is no history of mental illness of any kind.