Winter Weather Advisory – Cascades… Saturday 10 AM-Sunday 10 AM. The Winter Weather Advisory will remain for the East Slopes of the Oregon Cascades and the Upper and lower east slopes of the Washington Cascades through tomorrow morning. Snow levels will be 3500 ft with snow accumulating up to 2-5 inches along the upper east slopes of the Washington Cascades, patchy light freezing rain up to near 0.02 inches across the lower east slopes and 5-9 inches along the upper east slopes Oregon Cascades above 4500 feet near Santiam Pass level and 12+ inches along the crests.