New mapping will help spot the next Oso disaster

New mapping will help spot the next Oso disaster »Play Video
Crews work in the mudslide zone.

SEATTLE -- On an overcast Monday morning, March 24, less than 48 hours after the Oso mudslide killed more than 40 people, John Starbard drove to work with a sense of urgency he'd perhaps never experienced in his long career

As director of the King County Office of Permitting and Environmental Review -- the guy who has ultimate say in whether a building gets built -- he was anxious to instruct his top geologists and planners to scour their maps to see if what happened in Snohomish County could happen in King County. Was the next Oso in their midst?

But when he walked into the office and strode past the Vashon conference room, his team leaders were already meeting.

"They were already on top of it," says Starbard. "They were already mapping it."

The Oso mudslide disaster has rattled government planners by reminding them that saying no can save lives. Yet, of all those interviewed by KOMO 4 News, none of them believe "another Oso" sits within their purview.

Starbard chooses his words carefully to say: "We do not," he says. "We don't believe and we don't have evidence that we have something of a similar risk in unincorporated King County."

Nevertheless, many municipalities -- including Seattle, Snohomish County and King County -- are taking a closer look at their policies and upgrading their maps hoping to spot risky areas they may've previously missed.

King County unveiled late Monday a 2-year, $800,000 initiative to re-map unincorporated county land using lidar, the high tech aerial laser measuring that can see through trees and bushes to spot hidden landslide risks.

"The mapping that was done in 1990 didn't capture it well," says King County veteran geologist John Bethel, standing over lidar maps on a massive conference table. "It wasn't that the mapping was badly done. The technology just wasn't available."

He points to a lidar map of the Tolt and Cedar Rivers and says, "Then this (lidar) has become available and we've realized that mapping could be dramatically improved. And that's exactly the reason we are initiating the effort that we are right now.'

Stabard describes lidar like putting on your reading glasses.

You don't have to be a geologist or planner to wonder whether that steep hill near your house might turn into mud during the next heavy rainstorm.

In Oso, after the searching, the tears, and the funerals, the urgent mission now becomes making sure cities and counties communicate better with landowners in slide risk areas.

Davis Wahlman points to a map on his kitchen table showing his cabin overlaid with the path of the Oso mudslide.

"It's the very first one right there on the river. You come in Steelhead Drive," he says, "it's the first one on the right, right on the river."

It's gone now. His neighbors are dead, he says. Wahlman and his wife have been attending back to back funerals, and say they are alive solely because they happened to be away from their riverside cabin the day of the mudslide. Despite documents in the county bureaucracy suggesting a heightened risk, Wahlman says he was never informed.

"If you're not informed, you cannot make an informed decision," he says emphatically. "You can't make a risk assessment if you don't know what the risks are."

I asked Davis, "As someone who narrowly avoided being killed by this landslide, what is your message to local governments in this regard?"

"Clean up your act! That's my message," he says.

We showed the Snohomish County landslide risk map to James and Denise Moore, dedicated caretakers at the Masonic Campground east of Granite Falls.

"Yea, this is our loop and our park right there," James says.

"And the dark areas are slide risk areas," I say.

"Oh boy."

James is looking at red blobs on the map consuming his campground and the surrounding hillsides.

"That is quite concerning. Definitely."

"That looks exactly where our Dream Camp chalet would be," Denise says pointing at the map. "So that's our entire park!"

Their park is a slice of heaven right on the Stillaguamish River; The din of the rapids, chirping robins, moss hanging from trees. The swing sets are still now.  But on busy days, the park has 500 to 600 visitors.

Yet looming above the campground you can see logging. Clear cutting. A lot of it. On steep hillsides. The KOMO 4 Problem Solvers found that the map shows slide risk areas adjacent to many of those clear cuts.

We saw logging trucks hauling out a new load every five minutes, winding through trees, and crossing the Stillaguamish right past that campground.

James says he's heard no concerns from Snohomish County. He isn't a geologist but says "the conditions seem ripe for the same thing that's happened in Oso."

 The risk of landslides is not confined to the foothills of the mountains. Welcome to "The Summit," in Bellevue, with multi-million-dollar homes and priceless views. The neighborhood is perched atop a bluff near Cougar Mountain.

On the King County landslide risk map, the homes sit in a small white area surrounded by known hazard areas. It was unincorporated King County when developed about 25 years ago. Homeowner Kumar Narayanan now looks more cautiously at the designated slide risk area just beyond his backyard fence.

Standing on his deck high above the slope, I asked "When the Oso landslide happened, did you think twice about this hillside?"

"Yes, yes," he readily concedes. "We all had a chat about it. The children, my wife, and us. We came out and looked at the place."

He clarifies that he is not too worried about the hillside beneath his backyard. It's solid bedrock, say officials.

"The owners and the neighborhood are very particular about keeping all the trees there just to make sure that erosion is not an issue."

Slide risk areas on county maps do not necessarily mean a slide will occur. Yet, landslide risks can be anywhere.

In Issaquah, city engineers are monitoring the steep hillside north of downtown, with townhomes perched on top and a busy shopping center below. Landslide hazard map shows risk areas around it. Authorities believe it's safe. Extensive reinforcement was constructed by developers as part of the permitting process.

All three areas: the Issaquah hillside the view homes and the clear cutting  -- all approved by government regulators years ago using technology of the time.

That's about to change with King County's re-mapping. It will be able to:

  • reveal new slide risks.
  • find that some risky areas are actually safe.
  • predict what kind of slide could happen.
  • how far the debris field might shoot outward.

The county says slide warnings may attach to property titles, perhaps even to existing homes like yours.

"Yea, that could certainly happen," says Bethel, the county geologist. "There are certainly large areas of the county where building construction happened before the county was regulating landslides at all. So there are existing houses and existing building lots in areas of concern."

King County will also emphasize that landowners must share some of the burden of assessing their properties. Governments cannot know every detail about every piece of property, says Starbard.

Spotting the next Oso is difficult because it's an imperfect science, they caution. Regulators say if they knew of an imminent risk, they'd holler out loud.

The earth, says Starbard, is unpredictable.

The King County slide risk map is available here. The Snohomish County slide risk map is available here.  The Seattle slide risk map is available here.