High marks for disaster drill

Agencies simulate failure of Hungry Horse Dam

What would happen if Hungry Horse Dam burst over Memorial Day weekend?

In a nutshell, 75,000 residents and tourists would need to be evacuated, Flathead County's emergency command post at the Justice Center would be under water and an inland tsunami of Flathead Lake would send water rushing through Polson and as far away as Thompson Falls.

Flathead emergency-services and government agencies tested their response capability Wednesday in an impromptu simulated dam failure ordered by the governor's office.

The scenario for the surprise "table-top" drill was grim: Heavy snowpack and record rains caused massive cracks in Hungry Horse Dam, leading to a failure. Responders were notified of the impending disaster on the Friday before the Memorial Day holiday weekend. The dam would fail on Sunday, giving officials 48 hours to put their plan in action.

Flathead County Deputy Emergency Services Director Lynn Ogle said such a scenario is "really unrealistic, one in a million," but nevertheless, agencies stepped their way through the mock drill and Ogle was satisfied with Flathead's overall response.

Flathead responders got high marks from the state.

"Flathead County did a remarkable job," said Monique Lay, spokeswoman for Montana Disaster and Emergency Services. "What they did on such short notice was very impressive."

The first task was to simulate the evacuation of Hungry Horse, then West Glacier and the Blankenship area, Ogle said. Those residents would be taken east; most other evacuees would go west. And evacuation of roughly 35,000 to 40,000 on the valley floor would take a couple of days, he said.

There would be casualties. Some would refuse to leave; others would stay behind to loot.

"We estimated [deaths] at 1 percent of 35,000 people," Ogle said. "And that's not a bad estimate."

With the aftermath of Hurricane Katrina still on the minds of emergency responders, evacuation plans are always being fine-tuned, he said.

Though it's difficult to know exactly how far-reaching or how deep the flood water from a dam failure would be, officials believe portions of Columbia Falls and Kalispell would almost certainly be under water.

"My office would be under about 15 feet of water," Ogle said about the emergency-services center in the basement of the Flathead Justice Center. One of the first tasks in a flood situation would be to move the command center into a mobile dispatch unit.

Boxes of records stored at the county shops on Willow Glen Drive would also be in the water's path, Ogle added.

But some areas of Kalispell wouldn't be under water, such as the location of the Daily Inter Lake.

"You guys will be high and dry," Ogle said. "We could set up a dock at the underpass."

Whitefish, at much higher elevation that most of the valley, would escape disaster, Ogle said, although in a worst-case scenario some flood water could even back up into Whitefish Lake.

Bridges on the Flathead River and other tributaries would be lost, compounding the logistics of evacuating residents. The county plan expects U.S. 93 South to be impassable, so the Swan Highway (Montana 83) would be an emergency route. A dam failure also would cause an inland tsunami of Flathead Lake, with water spilling onto Polson and stretching as far as Thompson Falls.

"No matter what, that large amount of water has to go downstream," Ogle said.

The disaster exercise also was conducted in other affected areas, including Lake, Lincoln, Sanders and Missoula counties and Flathead Indian Reservation.

In Flathead County, the response came from myriad entities, including search and rescue organizations, the sheriff's office, schools, public health, area law enforcement, fire and public-works departments, Flathead Electric, Burlington Northern Santa Fe, Columbia Falls Aluminum Co., Northwest Energy, along with the county's Community Protection Incident Management Team and Local Emergency Plan Committee.

Grand Coulee Dam, which manages Hungry Horse Dam, was also called into the mix. The state Department of Transportation was involved, too. In addition to preparing an incident action plan for a dam failure, agencies were directed by Gov. Brian Schweitzer to develop a large-scale housing plan for 75,000 evacuees, using facilities in Idaho and Washington if needed, and develop a plan for restoring public services.

"By and large, it did go quite well," Ogle said. "Of course there's always room for improvement."

The drill helped pinpoint potential problems with communications and challenges that would accompany such a widespread evacuation.

Pete Wingert, patrol commander for the Flathead County Sheriff's Department, said he agrees there would be some "rough spots" in the event of such a catastrophe. Work still needs to be done to determine how the county's population is spread out through the valley - how many people live in Hungry Horse, how many in West Glacier, "that kind of legwork."

Wingert said he, too, was pleased with the outcome of the exercise.

"I was fairly proud of how we handled it," he said.

The governor's office issued a press release Thursday, noting that jurisdictions involved will submit reports for review.

"Everyone did an excellent job and I feel confident the state is prepared," Schweitzer said in the release. "It was also a great chance for everyone, including myself and my staff, to learn what our role would be if such a disaster were to occur."

Features editor Lynnette Hintze may be reached at 758-4421 or by e-mail at lhintze@dailyinterlake.com