Storm impacts on the beach: 27 November 2019

I had a chance to poke around Ediz Hook and Port Angeles Harbor a bit around high tide on 27 November 2019, during a strong northeast wind that coincided with high tide.  Waves were breaking over the coastal defenses on Ediz Hook (video above shot from the Coho ferry), as well as on to the Olympic Discovery Trail:



and not surprisingly, led to a bit of damage along the trail:



Beaches exposed to the northeast were also impacted.  I just happened to collected a few beach profiles on the east side of the Elwha River delta the day before this storm, so went back out afterwards to re-occupy those transects, one collected about here:

 and another a bit further east here:

Both of these beach profiles definitely show the impact of that event on the beach.  In both cases the upper beach eroded landward by anywhere between a fraction of a meter (a few feet), and up to roughly 3 meters (~10 feet).  I don't typically have the opportunity to capture this kind of event-driven change, and in fact these sorts of quantitative characterizations of event-driven change on the shorelines of Puget Sound and the Strait of Juan de Fuca are pretty rare...so I'm glad the opportunity came up. 

The anatomy of this particular storm was interesting to me.  The tide itself wasn't particularly high.  The tide gauge in Port Angeles maxed out at about 0.3 m (~ 1 foot) above MHHW:

and there was no storm surge associated with this event.  In fact, the high tide was suppressed a little bit, probably by the outward flow of air in the Strait (since the air pressure was low-ish during the high tide).  A water level of 0.3 m (~1 foot) above MHHW is nothing - we typically hit 0.3 m above MHHW multiple times a year.  What really made this event tick was wind, and in particular the strong flow of air out of the Strait, that led to sustained winds measured in Port Angeles harbor of 20 to 25 knots from the northeast.  The wind kicked up waves with significant wave heights exceeding 1.5 meters at the NOAA buoy in the Strait of Juan de Fuca, which is big, but not huge, for the Strait in November.  And this is really where we get to what made this event so interesting...it was the direction of the wind and waves...from the northeast...directed straight into Port Angeles Harbor, and straight at the end of Ediz Hook and the east side of the Elwha.

The waves breaking over the rip-rap on Ediz Hook (in the video at the start at this post) also provide an important bit of context.  I know from my survey work out there that the crest of the rip-rap sits at an elevation of roughly 2.5 meters (~8 feet) to 3.0 meters (~9.5 feet)  above MHHW.  Since we know that the water level at the time, as measured at the tide gauge, was 0.3 meters (~1 foot), we also know that water was being pushed 7 feet or more above the water level at the time, up and over the crest of the rip-rap.  So wave-related process, like wave run-up and set-up, were really important in making this event exciting.  Furthermore, we can actually use the event to characterize the magnitudes of those processes during an extreme event...and those sorts of observations are also relatively rare in Puget Sound and the Salish Sea.