Anatahan Volcano is a small volcanic island north of Saipan. It is about long and wide. Anatahan began erupting suddenly from its east crater on May 10, 2003, at about 6 p.m. (0800 UTC). It has since alternated between eruptive and calm periods. On April 6, 2005, approximately of ash and rock were ejected, causing a large, black cloud to drift south over Saipan and Tinian.