I will find blacks for about 3 weeks in the same patches but there will usually be 1 good flush where the patch produces several usually following that "perfect" 2-3 day stretch of weather. I notice that I tend to find my earlier blacks at higher elevations for example 800 ft above sea level versus say 600 ft. I think that is because of the air temps being warmer at the higher elevations. In your mountain areas that philosophy would be reversed at your more extreme elevations.