Painted Rocks Dam Burst Could Cause ’30 Foot Wall of Water’ to Hit Hamilton, Group Says
Over 180,000 people were evacuated in California this week as the Oroville Dam threatens to burst, now, some in the Bitterroot are warning that the same thing could happen here. Montana DPHHS has placed both Missoula and Ravalli counties at high-risk for dam inundation and a group called SOS the Bitterroot is asking for more to be done.
"We're concerned about dam safety in the Bitterroot, we have more high-hazard dams in the Bitterroot than anywhere in the state of Montana," said SOS the Bitterroot spokesman Dallas Erickson. "Two of them really concern us: Como Dam and Painted Rocks, we're concerned that neither of them have Early Warning Systems so that people in the Bitterroot would know what's coming if something happened."
Erickson says a FEMA-required study on a possible Painted Rocks Dam inundation paints a graphic picture of the risk the dam poses.
"It would take about two hours before that 25 to 30 foot wall of water hit Conner, then another hour or so to hit Darby, and it would cover Darby with that 30 foot wall of water," Erickson said. "Then, about five hours from the inundation, it would hit Hamilton, it would hit the hospitals, with a 40 to 50 foot wall of water: it would take out a lot of Hamilton, even the 911 center would be under 20-some feet of water."
SOS the Bitterroot is pleading with the DNRC to install redundant early warning systems. Erickson says the $10,000 cost of those systems is small compared to the potential deaths of citizens and billions of dollars in property loss.
Ravalli County Sheriff Steve Holton says Emergency Management Plans are in place for both dams and that practice drills have been done in recent years to prepare for dam inundations, but that there are no recent indications that such an event is likely.
Though he did confirm that the dams don't have an early warning system, Ravalli County Department of Emergency Services Director Erik Hoover says both dams are inspected by professionals every year and have shown no signs of weakening. In fact, during irrigation season, when dam inundation risk is highest, Hoover says the dams are inspected daily.
Montana’s most tragic dam inundation event occurred in 1964, when the Two Medicine Dam failed, leading to the deaths of 30 people.