As we reported yesterday, a new study says avalanches from Mt. Juneau pose an “unacceptable risk” to Capital City residents and property. The study also recommends the city buyout at risk homes. KTOO’s Casey Kelly reports.
Consultants from the Swiss Institute for Snow and Avalanche Research looked at Mt. Juneau’s Behrends Avenue and White Subdivision avalanche paths last year.
Over the centuries, slides have carved out huge swaths of hillside on the 35-hundred foot peak overlooking a pair of neighborhoods near downtown Juneau.
The report makes clear it’s only a matter of time before the next large avalanche impacts one of those neighborhoods, says the city’s Emergency Programs Manager Tom Mattice.
“They looked at the history from the early 1900s all the way to present and in the Behrends path they found three avalanches reaching tidewater, in 1890, 1926, and 1962. In 1962 only the wind event reached the tidewater. But in the other two events, snow mass reached the tidewater in great amounts,” said Mattice.
Computer model of a 30 year dry powder avalanche with a 1.4 meter depth in the Mount Juneau starting zones. Video courtesy of City and Borough of Juneau Emergency Programs.
The report says the most effective way to reduce the risk of avalanches from the Behrends path is to have the city buyout homes in the neighborhood below and prohibit development there.
Other measures – such as snow dams and retaining walls near houses, or snow supporting structures on the hillside – are too expensive and might not protect the neighborhood. The report says they could be effective in the White subdivision, which contains fewer homes, but there would need to be more study.
Likewise, Mattice says the consultants do not recommend using explosives to artificially release snow on Mt. Juneau.
“With a mean inclination of 34 and 35 degrees, those are very, very active avalanche paths,” Mattice said. “The worst case scenario is, we’d try and start a small avalanche, the avalanche zones connect to one another, we’d end up with a large avalanche and we’d be buying the houses.”
The report recommends the buyout, which would include at least 28 homes, be done in phases, targeting the most at-risk properties first. Mattice says the same Federal Emergency Management Agency grant that paid for the avalanche mitigation report could pay for a buyout.
“At this point in time, the recommendation would be after to approach the residents in area one, determine their level of interest, and after you’ve gained level of interest you could determine fair market value on those properties. Then use that fair market value to form cost-benefit analysis to apply for the grants for that first step,” said Mattice.
The buyout idea has been floated to city officials in the past. And while the assembly did not commit to any course of action, Assemblywoman Karen Crane said she hopes this report will not be ignored.
“I just hope this doesn’t end up another report – we’ve had several along the way – that ends up on the shelf, and that we can find a path to take some action here,” Crane said.
At a minimum, the report recommends mandatory evacuations and road closures when avalanche danger is most severe.
The consultants say Juneau Douglas High School, which is near the bottom of the Behrends path, would not sustain any damage even from the largest possible avalanche.