Northern Lights in Utah?

From Aurora Borealis Forcast

We were in Cottonwood Heights last night leaving my in-laws when we saw three strange flashes of light in the sky. Actually, I missed the first one sitting in the car but I heard my kids out on the lawn, "Wow! What was that?" I looked out and saw the second and third manifestations. The clouds above us flashed green and pink just for a second.

Having seen Northern Lights or the Aurora Borealis once in my life from the deck of our Alaskan Cruise ship, the colors seemed the same. But on the cruise, we saw them far in the distance on the horizon. Last night it was right above our heads. There was no sound associated with it.

I don't know what else it could have been. St. Elmo's fire? Ball lightning? Aliens?

Any ideas out there? Any other witnesses?