A video shot by a Snohomish County geologist provides a small glimpse into the power of the landslide hill near Oso.

Taken a month after the March landslide killed 43 people, the video shows a still-active hill shedding dirt and rock. The video starts off with dirt falling down the face of the exposed hillside. Then two large chunks of the hillside topple and slide toward the Stillaguamish River below.

“That’s a big one. Wow,” the geologist, Jeff Jones, says at one point.

The video was released to The Seattle Times in response to a public-disclosure request.

Chunks of the hillside have continued to fall since the deadly landslide, and county public-works director Steve Thomsen said the sloughing captured on video isn’t unusual as the hill tries to stabilize itself.

“Multiply that times 500, and you almost get an idea of what the big slide was like,” Thomsen said.

The March 22 landslide sent 10 million cubic yards of dirt rushing toward the Steelhead Haven neighborhood, according to a U.S. Geological Survey estimate. That’s enough material to fill 3,000 Olympic-size swimming pools — or four Kingdomes.

The video was a product of a little luck and a little bit of quick-thinking on the part of Jones. He happened to be up on the hill doing observation at the edge of the exposed scarp face. Because of the dangers, he was secured with a rope.

Jones noticed signs that a portion of the hill could topple across the scarp face to the east of him, so he got out his camera to capture the moment.

Thomsen said the chunks that fell didn’t make it to the river, although he wouldn’t rule out that a larger collapse could send debris that far. He pointed out that the end of the video shows how the debris begins flowing almost like a liquid.

The falling chunks are a result of the large landslide leaving overly steep portions of the hill. Thomsen said the hillside has grown less active, but officials expect sloughing to continue.

Mike Baker: 206-464-2729 or mbaker@seattletimes.com

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