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Earthquake triggers Mount Si rock slides
NORTH BEND - Many people witnessed two rock slides on Mount Si toward the end of last week's earthquake. But what looked like dust or smoke to those in town was actually a mix of gigantic boulders, smaller rocks and parts of trees.
"Each time there's a quake, there's a slide," said Zara Fritts, who has lived in the Valley since 1941 and has been through many earthquakes. She explained that this rock slide seemed a bit bigger than the one in 1949.
Cliff Knopp, who lives near the base of Mount Si in an area known as Ellisville, near Moon Valley, witnessed firsthand the slide's destruction.
About five minutes before the quake, Knopp decided to take a break from his workshop, and strolled a few feet to his house. He noticed that his cats, who normally hung around their food bowls near the house, had run off , which was unusual. He was in his Lazyboy chair right before the temblor shook his house.
"I was literally lifted right out of my chair," Knopp explained. "I knew it was powerful. I looked out the window and there was a huge cloud of dust, a rumble, and boulders going through the trees." He estimated the boulders to be about 6 to 8 feet in diameter. And he would know.
"It was right at the very end [of the quake] and I could hear a shock wave, a rumble, and saw the rocks coming down," he added. "It was so amazing, just like an explosion. Things were literally blowing off the top of the mountain." The slide took the tops of trees off, but fortunately, none landed on his neighbors' homes. Nearby, rocks weighing several tons lay near the riverbank from previous quakes and shakes.
The slide carved a light brown path, which Knopp estimated to be about 1,000 feet long, down the mountainside. A cloud of dust lingered 20 to 30 minutes after the slide.
"[The rock slide was] almost as concerning as the earthquake because I had no idea how much was coming down. I really thought that we'd lose a major part of the mountain, it was so violent," he said.
Knopp's home is positioned right on top of the fault that runs from Duvall to Mount Si, so he felt a strong shock wave, or current, go under his home before it rolled across the land and up the mountain.
In a later interview, he pointed out a crack that runs straight up the mountain, which geologists explained to him was the result of an earthquake thousands of years ago.
Knopp said he and his wife feel the vibrations when even a small earthquake hits in the region. And they are used to watching slides on the mountain, but not this big.
"Usually we hear rocks tinkling around, but this was massive," he said.
While Knopp was watching the slide on one side of the mountain, his wife, Carol, was witnessing the same thing, on the other side, on her way back fro the North Bend Library.
Other North Bend and Snoqualmie residents saw or heard the slide as well.
"From the direction we were at, it looked like a big puff of smoke. It looked like Mount Si was on fire," said Elise Cooksley, a science teacher at Two Rivers Alternative School in North Bend. Cooksley was playing with the school's new digital camera when the earthquake hit, and ran outside to take pictures of the rock slide.
"It was really loud. Not as loud as thunder but about that type of sound," said Two Rivers Alternative School student Amber Lane, 16, of the slide. "It looked like a big waterfall, just dirt blasting straight out."