Cape Shoalwater forms the northern entrance of Willapa Bay, but defining it precisely is tricky since it has been shifting north and shrinking rapidly for many decades. I guess the simple explanation is that the ebb tide channel that drains Willapa is migrating northwards - but just why this is happening and when it might change - is much more complicated.
Washaway Beach continues to wash away, at something like 100' every year. Because the retreating bluff is cutting through the street grid on a diagonal, it always tends to look sort of the same. It's always cutting across the road at an angle, there are always a couple of houses on the brink. There are always trees falling over the edge and old water pipes sticking out of the beach. A lot of homes have gone in since I first visited in 1990 - even since my last visit in 2010.
Washaway Beach: March 2010
Just east of Washaway, the migrating channel intersects older Pleistocene sediments. The highway is trapped against the higher, more resistant ground here - since all that's left to seaward are a few resistant knobs and a lot or riprap (and the old box culvert that I assume went under the old highway before the road was relocated).
Considerable effort and money has been spent to protect the road along here, including a large groin built just to the west about a decade ago. But the shore continues to retreat. During the past decade or two, the spit to the east (Graveyard or Empire) has unraveled and the Corps has recently carried a large nourishment project near Tokeland.