Dam Safety Awareness Day is observed nationally on May 31 every year to mark the anniversary of the Johnstown Flood, a flood that resulted from the 1889 failure of the South Fork Dam in Pennsylvania and caused the deaths of 2,208 people.  This remains the third largest loss of civilian life in a single day in the United States behind the 1900 Galveston Hurricane and the 9/11/2001 terrorist attacks.