I don't know how many people who don't live on the West Coast are aware of this massive landslide:
Washington State Mudslide: Over 100 Remain Unaccounted For In Snohomish County
But it sent me searching on the Internet for an answer to "Why were homes still being built there?"
"SEATTLE -- A scientist who documented the landslide conditions on a Washington hill that buckled last weekend in a massive mudslide warned in a 1999 report filed with the U.S. Army Corps of Engineers of "the potential for a large catastrophic failure."
The Seattle Times reports that report was written by Daniel J. Miller and his wife, Lynne Rodgers Miller. Daniel Miller told the newspaper, "We've known it would happen at some point."
Daniel Miller studies land formations and their changes. He also documented the hill's landslide conditions in a 1997 report for the Washington Department of Ecology and the Tulalip Tribes.
He says he returned to the Snohomish County hill in 2006 within weeks of a landslide that plugged the north fork of the Stillaguamish River and was startled to see new homes being built.
Snohomish County Executive John Lovick and Public Works Director Steve Thomsen said Monday night they were not aware of the 1999 report. Thomsen says a slide of this magnitude is "very difficult to predict."
Scientist says he knew 15 years ago hillside would fail | KING5.com Seattle
Here is a graphic that shows positions of old slides and this newest one.
The Snohomish County landslide - The Washington Post
"~ At least five homes were built in 2006 on Steelhead Drive in the path of Saturday's event and another home was built in the neighborhood in 2009.
~ The hill that collapsed Saturday is referred to by geologists with different names, including "Hazel Landslide" and "Steelhead Haven Landslide," a reference to the hillside’s constant movement. Some residents, according to a 1967 Seattle Times story, referred to it simply as “Slide Hill.”"
DEATH TOLL IN MASSIVE SNOHOMISH COUNTY MUDSLIDE INCREASES TO 14<br><i>Some 176 people unaccounted for</i> | FEATURE NEWS | Sky Valley Chronicle Washington State News