Varner and Sarah go looking for him as a dust storm begins. A dust storm settles over the battle. Arvin suffered further damage on December 20, 1977, when a dust storm hit the area. The region is prone to occasional, violent dust storm, which can severely reduce visibility. This "dust storm" effect would be strongest at the Moon's terminator. The dust storm would also explain the poor image lighting. In 2015, an unprecedented dust storm hit Syria and Iraq. As there was a dust storm blowing at that time, he was not recognized. In a major dust storm, dunes may move tens of metres through such sheet flows. One of them, "Great Dust Storm", describes the events of Black Sunday. In 2009, dry conditions brought a severe dust storm towards eastern Australia. A severe dust storm threatens to topple their Mars Ascent Vehicle (MAV).