Astronomy - Asteroids

Last night at 6:50 pm, MST, there was a very bright light flash across the sky north of Park City, Utah. Did anyone else see it? As no stars were visible at that time, it was so bright that it appeared to be rather close to the earth. It was headed in a northerly direction. I have also been fascinated the past few days with the linear line-up of Venus, Saturn, the Moon and Mars in the early morning hours. How often does this occur each year? Thanks for any input.