The Redlands Dam, an earthen dam on Cataract Canyon [corrected 9:25 pm, 8-17-08] near the Grand Canyon, failed early this morning after heavy rains the past two days, causing evacuations of hundreds from campgrounds and the town of Supai, on the Havasupai Reservation [right, National Park Service].
Information on Redlands Dam is hard to find because of national security concerns. Links to dam safety web sites are limited to authorized personnel.
Update - by Monday afternoon, Aug 18, authorities reported that the dam breach played a minor role in the flooding. The primary cause was heavy rains over the preceding two days.