Long icicles hang from the roof of a building on F.E. Warren Air Force Base, Wyo., April 18, 2013. Icicles, while lovely, may cause harm by falling or forming ice on the ground, and people should tread carefully around them and avoid standing beneath them. People who notice potentially dangerous ice on their work centers’ roofs should contact their facility manager to have it removed. (U.S. Air Force photo by R.J. Oriez)