With the death toll at least at 8, and over 100 people still classified as missing,  officials are searching to find the cause of the massive mudslide near Oso, WA. Pictured are members of the Langston family, who's home in Darrington was flooded by displaced river waters from the slide.  They're in one of a number of Red Cross Shelters.

According to KING 5-TV,  there are several potential causes.  The Department of Natural Resources says similar slides occurred in the area in 2006.   While there's been no seismic (earthquake) activity,  geological conditions, previous activity and heavy rainfall are likely culprits.

The National Weather Service reports recent rain has been 200% of normal over the last 45 days, 15 inches above normal.

The 1-square mile mudslide is estimated to be 15-feet deep in places.  The debris from the slide is blocking a one-mile stretch of Highway 530.  Oso, WA is about 55 miles North of Seattle.