Last month, we were excited to share an image of a twister on Mars that lofted a twisting column of dust more than 800 meters (about a half a mile) high. We now know that’s nothin’ — just peanuts, chump change, hardly worth noticing. The Mars Reconnaissance Orbiter has now spotted a gigantic Martian dust devil roughly 20 kilometers (12 miles) high, churning through the Amazonis Planitia region of northern Mars
From here. There are videos and stuff online as well.