19 December 2015

Florence, Oregon: a fatal landslide triggered by intense rainfall

Posted by Dave Petley

A fatal landslide in Florence, Oregon

At about 3:20 am on Friday morning a fatal landslide occurred near to Florence in Oregon.  The landslide, which is described in some detail in an article in the Register-Guard, struck the rear of the house of a local resident:

At about 3:20 a.m. Friday, Dolores Miller heard clawing inside the back door of her Florence-area vacation home and went to let one of her two dogs out.  And just then the home was hit by a lethal wall of trees, mud and other debris that cascaded from the rain-drenched adjacent hillside … Miller’s husband “heard a scream and he went to look for her and all the mud was in the house,” said Sean Barrett, fire marshal for Siuslaw Valley Fire and Rescue.  The landslide filled the home of Miller and her husband, Gary, and knocked a neighboring home two feet off its foundation on Santa Road, a private road off Mercer Lake Road.

The article also has some images of the landslide, including this excellent picture of the source area:


Florence landslide source via the Register-Guard


Whilst this image, from KATU2, shows the aftermath at the location of the house:

Florence landslide

Florence landslide via KATU2


A very interesting aspect of this landslide is the fact that it appears to have initiated directly below the road.  I suspect that those who are investigating this landslide will be interested to know whether the road was partially located on fill, perhaps to create a sufficiently wide road bench on the bend, and on how water was being managed around the road.  But I have no indication that either of these things were a factor. The event certainly illustrates the danger of even quite small slope failures if someone is unlucky enough to be in the path.

This part of the USA is currently suffering very heavy rainfall, so the risk of landslides is perhaps unusually high.