3 triangular shaped ufos over an empty field in Riverside, CA with beams of light searching the field; no noise, no wind, not copters

On the way home from grocery store, saw lights going off an on over an empty field in Riverside, just outside our housing tract.  pulled to side of road to try to see what it was; window was down and there was no noise, as from a helicopter.  Looked up and saw 3 triangular shaped ufos, looked like very heavy metal, no noise, no wind, just beams coming from one going off and on as if searching for something in the field.  All 3 started moving very slowly across the field and I watched them as they crossed over the highway below and slowly disappeared.  I can draw what they looked like, rough sketch, but saw another drawing by someone else many years later on a television special, not same time or area though.  My daughter was with me at the time but she was only 5 or 6, don't remember exactly, and she only has vague memory of this happening.  Went home right afterward and told my husband about it; he believed me because he knows me.
Date is approximate.  PD