Thursday, July 02, 2015

Elmira Street

Elmira Street Park, on the north edge of Port Townsend, is locally known as The End of the World. This may be a bit of an exaggeration, but it's certainly the end of the trail. It got a lot of attention two winters ago when some large chunks fell away (see video from 2013 below).

I visited the top briefly in April*, but stayed back from the edge and didn't linger, even though the likelihood of anything happening during my brief stay was low. But it's always hard to know how undercut the bluff is or what might trigger a collapse.

These bluffs of glacial drift are fairly coherent, form a steep face, and tend to fail as large slabs. These topples from the upper half of the bluff are encouraged by gradual erosion of the underlying units and by wet periods and/or freeze-thaw events.  The collapsed material is quickly redistributed by waves and in this case most is destined for Point Wilson a couple of miles to the east.

There is a small concrete observation post dating to World War II at the edge of the bluff. Rough estimates of erosion rates along here are 6 inches per year, but that suggest the structure was built 30-40' back from the edge (in the forest?)  I suspect it was built closer than that - better views of the water - and retreat isn't as rapid as those earlier estimates.  Dramatic when large slabs fall, but not the end of the world.

* I'm embarrassed to point out that this visit occurred way back in early April. This spring things fell behind, in part because of a slow-moving hard disk failure that took a long time to diagnose, then to replace. I liked my little Sony laptop, but when faced with the need to retire it, I decided to switch back to a Mac. For those who care, I rely heavily on Picasa to manage photos and it seems to run very nicely on the Apple.

Over the next week or two? I will try to gradually backfill both this blog and my companion hshipman blog with posts I drafted this spring while my hard disk was grinding to a halt.

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