Sister Bonnie Boilini sends us this intriguing photo and asks, "Why is it when you are out West, the streaks in the clouds showing rain are sometimes black and white?" I certainly see why you ask the question after looking at this photo. I've shown it to my colleagues here in the office and, without being there to witness this scene first hand, we can only speculate.
But our best guess, Sister Boilini, is that what we're looking at here are a series of rainshafts--several of which may involve microbursts which hit the ground and kick dust into the area. The ones which appear white are being illuminated by light. You see this sort of phenomenon on the Front Range of the Rockies in eastern Colorado with some frequency. Rainshafts in the shadows appear darker.
It's worth noting that when you see white streaks emanating from the base of a thunderstorm, it's not uncommon for them to be hail shafts--columns of hail pouring out of the thunderhead above. Sister Boilini tells us the picture was taken near Antelope Canyon in Page, Arizona, and that she had just gone through a terrible storm. Great beautiful photo, Sister Boilini--thanks for sharing it with us!
Photo courtesy of Sister Bonnie Boilini