Unknown Cloud Around Object and changed color then vanished

myself wife girlfriend at time and two step children were living in a small town called Crystal nevada 25 miles from the nevada test site it was about 11:00pm possibly 10pm we were walking down the towns main road when we saw a large white cloud in the clear night sky as we watched we saw what looked like a helicoptor with it's spotlight on flashing around in the cloud like it was looking for something after about 20 minets the light was gone the cloud started to get a brighter blue and then just faded away and was gone there was no sound at all it was there then it was gond i almost for got the cloud was i'de say 100 feet directly in front of us and about 100 feet in the air it was a white cloud before it turned blue and vanished there were other sightings but this is the first i reported even though it has been a while a computer was not avilible at the time  there was another where myself and some friends lost 2 hours after we went around a turn in the mountains we ended up at the end of the highway we were on wondering what happend i have not reporthd any of these sightings because i know how UFO sightings are treated when reported