Wash. and Tribal Officials Tried to Fend off slides
By John Ryan/KUOW
Saturday's deadly slide was the latest in a long string of landslides to hit the area known as the Hazel Slide along the North Fork Stillaguamish River. State and tribal officials have been trying to fend off slides at that spot for half a century.
The Tulalip Tribes were so concerned with landslides hitting the river and its prime salmon habitat that they blocked a proposed timber sale above the Hazel slide.
Kennard: "This had been known at least since the 50s as one of the more problematic areas on the Stillaguamish for perennial landsliding."
Geologist Paul Kennard worked for the Tulalip tribes in the late 80s. A timber company had clearcut part of the slope above the landslide zone. The tribes reached a settlement stopping an expansion of the timber sale.
Kennard: "It was our contention that the harvest"
That's land-manager-speak for "logging"
Kennard: "…harvest in the area just above the slide would increase the amount of groundwater, and essentially the largest factor in causing the slide was an increase in groundwater."
Geologists say without big trees to suck up rainwater, more water runs underground, where it can lubricate the already unstable soil in landslide zones. That's why the state has restricted logging above landslide-prone slopes like Hazel for the past 14 years.
Kennard: "On the Hazel landslide, the one we're talking about, it's happened four times. There was cutting in the 1940s; it failed in the 50s. There was cutting in 1960, then it failed in the mid 60s. There was cutting in '88; it failed in '91. There was cutting in 2005, and it failed in 2006 and in 2014."
That latest clearcut in 2005 was much smaller than earlier cuts. Kennard says it would take a geotechnical study to know whether the recent logging affected Saturday's slide.
KUOW has identified two current landowners of the area above the slide. The Washington Department of Natural Resources and Ken Osborn of Grandy Lake Forest Associates in Mt. Vernon did not respond to requests for comment.