Professor: Stop development in slide-susceptible areas

We’ve all known that Washington has its share of landslides. Now, we know how deadly a big one can be. So are we going to do anything before the next one?

Professor Nick Sitar is a geological engineer at the University of California, Berkeley and has been following the story from the beginning. Sitar said there’s no reason why geological information already being collected by county surveyors can’t be made available to the public.

The State of California issues a series of hazard maps that identify landslide hazards, and homeowners are supposed to be advised to consult the maps before buying.

But sellers, as you might imagine, are not eager for this information to come out.

“Homeowners in general are not particularly happy to see somebody like the U.S. Geological Survey, or in the state of California, the California Geological Survey, survey a hill-slope and conclude that it’s susceptible to landslides and designate the area as a potential landslide area,” said Sitar.

According to Sitar, people who have lived in their home for 50 or 60 years often say, ‘Hey, nothing has happened, and now you tell me there’s a potential landslide and my property is no longer as valuable as it was before?’

He’s in favor of making all of the geological survey information public. As for the accuracy of predicting landslides, we’re talking about rare events.

And there is a problem in predicting rare events.

“So let’s take a scenario, that in 2006 the state came in and said, ‘You know what, this is really dangerous, we have to move everybody out,” Sitar explained. That’s when the political process starts and manages to get everyone to move out of their slide-susceptible homes. But six years later, those houses are standing there abandoned, and nothing has happened.

“For a lot of people, they look at it and say, ‘What? You moved us out for absolutely nothing and this was just a great overreach by the government.’ And this is the really, really difficult part. It’s easier to stop development on areas that are unstable before it happens,” said Sitar.

For Washington, it instead might be wiser to undertake some sort of statewide survey so that before development happens, the areas that are dangerous have already been mapped out.

According to Sitar, that makes sense from the technical side of things: to develop maps of hazard zones. These maps would be similar to those that indicated flood zones.

So, the safest option is to stop developments in sensitive areas. You might ask, why not shore up the hillside. But in the case of something as large as the Oso mudslide, the cost of shoring up the hillside would far exceed the value of the property being protected.

MyNorthwest.com’s Alyssa Kleven contributed to this report.