So what if the Hungry Horse Dam broke?

By CHRIS PETERSON / Hungry Horse News

The Bureau of Reclamation will have a meeting next month and in October to go over Hungry Horse Dam failure scenarios with local emergency management officials.

The first is an orientation meeting, scheduled from 9 a.m. to noon on Sept. 10 at the Hampton Inn in Kalispell, said Dennis Philmon, facilities manager for the Hungry Horse Dam.

That meeting will get agencies together, take comments on emergency plans and work out the proverbial kinks toward doing a real exercise.

The next meeting, held Oct. 16 at the Hampton Inn, will be a "table top" exercise, where managers actually run through a scenario of a dam failure.

The odds of the dam breaking are small, Philmon noted, but there is some potential. A large earthquake, for example, could compromise some or all of the structure.

Earthquakes in Montana are not out of the ordinary.

According to a 1997 report by earthquake expert Michael Stickney of Montana Tech in Butte, in four decades from 1920 to 1960, an earthquake of at least magnitude 6.0 struck western Montana roughly once per decade.

The most famous earthquake measured 7.5 on the Richter Scale at Hebgen Lake on Aug. 17, 1959.

Twenty eight people were killed — 26 of them by a 43-million cubic yard rockslide across the Madison River.

James Dean, regional emergency management coordinator for the Bureau of Reclamation, said there's an active capacity of about 3.086 million acre feet of water behind the dam. An acre foot of water is a foot of water spread over one acre.

In short, if the dam were to fail, towns like Hungry Horse and lower parts of Columbia Falls would be destroyed.

But Dean noted that recent tests of the Hungry Horse Dam itself and its surrounding rock abutments performed well in earthquake tests.

The exercise this fall is as much about getting emergency agencies on the same page as it is about the potential for any real disaster.

The Bureau has these exercises with local, state and regional governments about once every three years, Dean noted.