Mountain Rainstorm depicts a storm that rushes in quickly and then gracefully recedes into the mountainscape as swiftly as it arrived, something that happens frequently in the afternoons in the Rocky Mountains. This lively post-minimal piece features broken octaves in the left hand that only happen on black keys. It begins in E-flat Dorian and ends in G-flat major. The time signature regularly alternates between two measures of 6/8 with two measures of 7/8, but the composite rhythm between the hands is simply steady eighth notes.