An example of the speed at which weather changes in Colorado. This picture was taken as a few clouds were just forming. Minutes before the sky had been crystal clear. The next picture was taken less than an hour later as the clouds had grown significantly. On my way down it looked like thunderstorms were imminent and it rained a bit. I did hear some distant thunder, but never saw any lightning. It is really difficult to predict what days the weather will be like this. The best way to avoid it is to be done hiking before 11am which is not really reasonable for longer hikes.