A roof flashing that can be installed around a pipe, instead of over the pipe, is provided. The roof flashing can include a collar, a base, a foot, and a longitudinal opening. The collar can have a conical shape. The base can have a top edge and a bottom edge, the top edge of the base coupled to a bottom edge of the collar, the bottom edge of the base having a diameter larger than a diameter of the top edge of the base. The foot can be coupled to the bottom edge of the base and extend outwardly from the bottom edge of the base. The longitudinal opening can extend from an apex of the collar to an edge of the foot, and a width of the longitudinal opening can increase when first and second edges of the opening are pulled away from each other.