Alba Mons Dark Streaks

This VIS image shows several dark streaks near the summit of Alba Mons. Similar large, dark streaks are found on all the Tharsis volcanoes. This type of dark streak does not form due to surface winds flowing around topographic features like craters. Instead these streaks seem to form from in response to large slope winds blowing over the volcano. Such winds are called orographic winds, and are caused by air mass movement around mountains.