Last year’s Oso landslide revealed a huge gap between what geologists know about landslide-prone areas and the amount of information that trickles down to the people who live there.
In all the meetings, panel discussions and brainstorming sessions he’s participated in since the Oso landslide, University of Washington geotechnical engineer Joe Wartman has heard the same question posed in different ways: Where are the other Osos? Which other slopes have the potential to collapse with the kind of deadly force that left 43 people dead in Snohomish County last spring?
“I still don’t have an answer for that,” said Wartman, who was part of the first scientific team to study the slide. “We just don’t have a good inventory of our landslide hazards.”
As the anniversary of the slide approaches, Wartman and other experts are doing their best to keep a spotlight on the issue and ensure that lessons learned in the tragedy are translated into action.
Foremost among the needs are better maps to identify hazardous slopes, and better methods for communicating that information to homeowners and local governments, said UW geologist Kathy Troost, co-organizer of a forum this week in Seattle that she hopes will galvanize support for improvements.
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Oso revealed a huge gap between what geologists know about landslide-prone areas and the amount of information that trickles down to the people who live there, Troost said.
“Somebody has got to speak up for these homeowners,” she said. “I think it’s almost criminal for us not to do something to try to improve communications.”
County officials concerned about the landslide danger considered buying out the neighborhood destroyed by the Oso slide — but many residents were unaware of those concerns.
This week’s two-day forum, sponsored by the Association of Environmental and Engineering Geologists, will bring together land-use planners, insurance experts, government geologists and consulting engineers from across the country. Interest is so high that if space weren’t limited, attendance would probably be double the 200 people expected, Troost said.
Since Oso, King County has expanded its landslide-mapping efforts. Washington’s Department of Natural Resources is seeking $6.6 million to expand and improve the state’s landslide inventory and hire several new geologists. At the national level, President Obama’s fiscal year 2016 budget adds $500,000 to the U.S. Geological Survey’s landslide-hazard budget.
“Momentum seems to be building,” said Jonathan Godt, leader of the USGS program.
Among the thorniest questions is how to regulate land use in areas where landslide risk is high, Wartman said.
In Christchurch, New Zealand, where a 2011 earthquake triggered dozens of rockfalls and landslides that damaged hundreds of homes, the local government conducted risk analyses to estimate the odds of future slides. In areas where the risk was highest, homeowners were offered buyouts. No one was forced to move, but those who stay won’t be eligible for insurance coverage, said Wartman, who consulted on the project.
North Carolina launched an ambitious mapping effort in 2004, after hurricanes triggered more than 400 landslides in the state’s mountainous areas. But after four counties were mapped, the Legislature pulled the plug, partly because people feared regulation would follow and property values would drop, said Jennifer Bauer, a former state geologist.
Now a private consultant, Bauer has continued some of the mapping with nonprofit funding. Local residents are consulted early in the process and kept informed throughout, she said. And instead of being resentful, people have welcomed the knowledge — and the power it gives them to take steps to protect themselves and their property.
“It helps them know what they’re getting into, and how they can avoid or prevent landslides from happening,” Bauer said.