Has there been more coastal flooding on the Strait of Juan de Fuca recently?

 

Three Crabs Road on the Dungeness River Delta on 1/3/2026.  Photo by Rob Casey 

I feel like I've been having numerous conversations in the past few months regarding whether coastal flooding in the low-lying zones on the Strait of Juan de Fuca, particularly the neighborhoods along the Dungeness River Delta, have been occurring more frequently in recent years.  

And the answer, after at least a preliminary look at some tide gauge data, seems to be yes. 

Here is how I approached this. First, there isn't a tide gauge or other water level measurements from the Dungeness River delta, at least that I have access to, but the tide gauge at Port Angeles seems to do a pretty good job in terms of reflecting what happens at the Dungeness River delta. During a 2018 flood event, for example, I was able to relate the surveyed elevations of flood lines along Three Crabs Road to water levels measured in Port Angeles. 

Another one from Rob Casey from 3 January 2026, taken from here looking north.

My analysis of the 2018 event also provides some insight about how high the water has to get to cause flooding on the Dungeness River delta. But I actually think that the photo at the top of this post, from here during an event on 3 January 2026, is also useful for that purpose.  First, the coastal water level on 3 January 2026, when this photo was collected, reached 2.72 feet relative to MHHW, just high enough to send water across the road. Next, it also generally corroborates the flood elevations from the 2018 event I wrote about here in my blog. In my mind, therefore, and for the purposes of what follows, I viewed that coastal water level elevation of 2.72 feet MHHW as a useful threshold for evaluating the frequency of flooding along the Dungeness River delta - when water measured at the Port Angeles tide gauge reaches or exceeds 2.72 feet MHHW we can assume that flooding is likely happening at least along parts of the Dungeness River Delta.

Therefore, to get a sense for how often water makes it high enough on the Dungeness River delta to start flooding things like roads, and whether that has occurred more frequently recently, we can ask a relatively straightforward question: How often has the water measured at the Port Angeles tide gauge exceeded that selected threshold of 2.72 feet relative to MHHW? 

Here is the entire coastal water level record from Port Angeles, dating back to 1979, where the water level is shown as feet relative to Mean Higher High Water (MHHW).  I've added a red dotted line at that key 2.72 feet MHHW threshold:

and here is a zoom into just the top of that figure, with a few annotations, to hopefully highlight when those extremes occurred:

On this plot there are two distinct time periods that I've marked with arrows, the winters of 1982-1983 and the winters of 2003-2006, during which there were a number of water levels measured at the tide gauge that were high enough to presumably drive flooding on the Dungeness River delta. There was presumably some flooding during those two time periods, but I am unfamiliar with reliable records documenting flooding during those time frames. The winter of 2006, at least, was notable for driving significant storm damage at Seashore Lane, which is documented in the Washington's Marine Shoreline Design Guidelines. 

After that 2003-2006 time period there is roughly a decade of relative quiet, with just one event in November 2011 that exceeded the threshold that I'm using here. 

But the main takeaway...from 2015 to the present though there are five events that exceed the threshold, one every other winter on average. That seems to square with the general feeling the people seem to have that there have been more flooding events than usual in that area. Four of those events fall on to this list on NOAA's coastal inundation dashboard for the Port Angeles tide gauge, which is intended to capture the top 10 events on record for the tide gauge. 

This begs the question...why?  I don't have a great answer to that, but there are two candidates I would like to examine.  First, even small amounts of sea level change can drive changes to flood frequency, but it isn't immediately obvious that is what is going on here. The second option is a cool tidal phenomenon called the lunar nodal cycle, that I explore a bit here, or oceanographic anomalies drive by ENSO, may be partly responsible. I'm afraid it will take a bit of digging to really work that out.