Just when it seemed I couldn't be surprised by events in Iraq, I see the story of the Mosul Dam.

The largest dam in Iraq is in serious danger of an imminent collapse that could unleash a trillion-gallon wave of water, possibly killing thousands of people and flooding two of the largest cities in the country, according to new assessments by the U.S. Army Corps of Engineers and other U.S. officials.

Even in a country gripped by daily bloodshed, the possibility of a catastrophic failure of the Mosul Dam has alarmed American officials, who have concluded that it could lead to as many as 500,000 civilian deaths by drowning Mosul under 65 feet of water and parts of Baghdad under 15 feet, said Abdulkhalik Thanoon Ayoub, the dam manager. “The Mosul dam is judged to have an unacceptable annual failure probability,” in the dry wording of an Army Corps of Engineers draft report.

U.S. officials are aware of the disaster-waiting-to-happen, and initiated a $27 million reconstruction project to help shore up the dam. So what happened? “Incompetence and mismanagement” have marred the project.

The Army Corps of Engineers’ draft report describes this as “the most dangerous dam in the world,” adding, “If a small problem [at] Mosul Dam occurs, failure is likely.”

Iraqi and U.S. officials realize how serious the situation is, but have decided not to tell Iraqis, for fear of scaring them. I’m not an expert on such matters, but if a trillion-gallon wave of water may burst through an unsafe dam and put much of Mosul under 20 meters of water, shouldn’t the Iraqi citizens be frightened? Maybe if these citizens knew, the problem may be more likely to get fixed in a hurry?