Sunday, January 22, 2023

Winter Field Work

I have developed a preference for geology field work in the winter. Geology field work in western Washington State is generally pretty easy. The hardest challenge in western Washington is the thick vegetation. If you do not like smashing through brush, western Washington off trail field work is not the place for you. In the winter the vegetation is less dense with leaves off of the deciduous trees and bushes. However, Himalayan blackberries with their long canes and thorns still present a problem. On a recent excursion to a slide complex my initial thought was navigating on the slide complex might be limited due to the thick blackberry growth over much of the slide area. However, as I made my way onto the slide I realized the mid December heavy snow followed by freezing rain at the site had flattened down the much of the blackberries making my traverses on the slide complex much easier than initially anticipated. 

I still had to high step a bit to get over the blackberries but it was much easier than if done at another time of year. 

I caught another break with winter weather making my traverse easier after a couple of days steady temperatures well below freezing and before a big snow. I muddy slog with mid shin water and muck. I had been across the same area before. Though the site looked very wet the freeze allowed for easy walking across the frozen mud and frozen ponded water.

The weather does not always work out but, there are the other added benefits: no bugs, easier to see where water has been flowing, and not much worry about dehydration.    




Wednesday, January 18, 2023

The Penn Cove Whale Watchers

Many of my shore walks to visit slides and bluffs are non social events. I most often do not see anyone particularly on chilly breezy day in winter. But on this trip on southeast corner of Penn Cove on Whidbey Island I came across a group with long camera lenses. Their aim was well out in the water beyond my ability to see with my own eyes and out of my field point and shoot camera.  

The whale watchers looking out over Saratoga Passage with 
Camano Island across the water and Mount Baker and Twin Sisters in the distance

 The group was tracking a pod of Orcas and with their lenses were able to identify specific wales by their dorsal fins. 

Penn Cove was the location of a rather notorious Orca capture in the early 1970s when Orcas were herded into Penn Cove and young Orcas were taken from the pod and at least 5 Orcas died. 

Sunday, January 15, 2023

Sea Level Rise: Notes on the December 27, 2022 Tide Flood

Back in mid December I visited a dike on the distal Skagit River delta area near Samish Island. The dike holds back high tides from Alice Bay from inundating the low farm fields and road. My site visit took place during high tide. During low tides Alice Bay typically fully drains becoming a broad mud flat.  

Samish Island Road and the dike between the road and Alice Bay.
The road is below sea level

View of the dike looking north. Alice Bay on the right, the east end of Samish Island is in the distance and the Chuckanut Range in the far distance 

View looking south along the dike.
Grassy areas in the near distance are saltwater marsh.

Dike District 5 portion of dike. This section of dike was and lined with with rock last year.

Last February there was a tide surge that caused tidal flooding in Edison. The minimal free board and dike erosion resulted in significant dike raising by the District. However, the district boundary ends between the above shown new work and the high ground to the north at Samish Island.

On December 27, 2022 a very deep and broad area low pressure storm system combined with very high astronomical high tide. The low pressure path and associated wind pattern added to the water levels. At Port Townsend the storm tidal surge was 2.5 feet.

    The result was water overtopping the dikes shown  above. 

Sea water over topping the a low spot in the dike

Multiple over flow locations along dike and water filling the low area behind dike including the road

Tide flood water pouring across road into fields to the west.

Flooded fields viewed from the north

While the above shown flooding covered on the order of 150 acres of fields with sea water, the impact for other areas was more acute. Flooding was reported at multiple locations from this event including Olympia and Port Townsend. 

North shore of Samish Island looking east.
Note that water just reached the top of the slightly elevated area between the homes and Samish Bay.

From the same location above but looking west.
Note here that the berm between the homes and bay is lower allowing flood waters to reach the homes.

Water getting over or around the elevated shoreline berm flooded the whole low area behind the berm. I had some work to do at this area and the water over topped my rubber boots. Not particularly pleasant as the flooding included flooding all the septic systems.  

Sea level rise is pushing what in the past had been a close call tidal flood to full out flood events with a higher frequency.