FIG. 1 is a front perspective view of a sloped wall roof flashing, showing our new design; FIG. 2 is a rear perspective view thereof; FIG. 3 is a front elevation view thereof; FIG. 4 is rear elevation view thereof; FIG. 5 is left side elevation view thereof; FIG. 6 is a right side elevation view thereof; FIG. 7 is a top plan view thereof; and, FIG. 8 is a bottom plan view thereof.