Monday, December 16, 2013

Aurora Avenue Landslide, Seattle, 1985

For a couple of years in the early to mid 1980s, Aurora Avenue along the east side of Queen Anne Hill in Seattle was periodically blocked by landslides. Besides property damage the slides were troublesome for traffic - Aurora is a main north-south highway and in hilly Seattle the alternative routes are limited. I have a couple of pictures I took of one of the larger slides from below Aurora and on Aurora.
Aurora landslide, Seattle, 1984-1985

Aurora landslide, Seattle, 1984-1985
A fair bit of engineering work has taken place on this steep unstable slope. The primary problem is a very compact silt/clay unit that causes water to become perched on top of it causing the soil layer above to become saturated. Sort of like sand castles becoming saturated at the beach. There are similar unstable slopes on the steep drumlin slopes of several areas in Seattle. These slide prone areas are bits of forest land in an otherwise very urban landscape. 
Green belt on east side of Queen Anne Hill, Seattle

1 comment:

Jill said...

I remember one of those huge landslides and seeing it across Lake Union from Eastlake. It was a big deal! Yes, developers get permits to build in places they should not IMO. thanks for the memories.