Mt. Shasta, Lassen Peak ready to erupt? Counties’ plans provide no specifics on evacuations

December 19, 2011 – CALIFORNIA – While a catastrophic eruption of Mt. Shasta or Lassen Peak could destroy huge swaths of the north state, local counties recently have approved vague disaster plans that assume critical details will be worked out on the spot. Geologists at the U.S. Geological Survey say there’s a one in three or one in four chance Mt. Shasta could erupt in north state residents’ lifetimes. While Shasta and Siskiyou counties’ “hazard mitigation plans,” drafted this fall, discuss the various risks associated with an eruption and identify key facilities at risk, the documents offer no specifics on how the counties would handle the mass evacuations of entire towns. They don’t address how they’d cope with choking clouds of toxic gas and ash, highways buried in volcanic debris or lava flows and threats to power transmission lines or other mass infrastructure failures. Shasta County’s plan has been approved by state officials, although it’s awaiting clearance from the Federal Emergency Management Agency. Siskiyou County’s plan, which remains open for public comment through the end of the month, is similarly short on specifics. Instead, the plans primarily rely on the assumption that federal geologists monitoring the volcanoes would give county officials plenty of warning, enough time for them to decide what to do. But volcanic experts caution that’s not always a given. When Mt. St. Helens first erupted in 1980, geologists had about a week’s notice, said Carolyn Driedger, a hydrologist and outreach director for the U.S. Geological Survey’s Cascades Volcano Observatory in Vancouver, Wash. “Yes, they do give warning, but it’s highly variable how much warning,” she said. She said geologists in Oregon and Washington have met with local governments to develop ‘coordination plans that spell out precisely what to do if we have volcanic unrest,” so “it’s not unusual for you to question” why north state disaster planners haven’t done the same. Pat Minturn, Shasta County’s public works director, said the county plan intentionally avoids some details. He said recent large-scale urban disasters like the Loma Prieta earthquake in 1989 and Hurricane Katrina in 2005 proved it’s impossible to plan for every scenario. “It always throws you a left hook out of nowhere,” he said. Mt. Shasta last erupted in 1786. –Redding