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. 

Notes on Sweet and others (2022) Seal Level Rise

Earlier this year Sweet and others(2022) updated Sweet and others (2017): Global and Regional Sea Level Rise Scenarios for the United State. Sweet and others (2017) suggested global sea level (GMSL) will rise as between 0.3 meters and 2.5 meters by 2100. Sweet and others (2022) find the high end of 2.5 m by 2100 less plausible. The bad news is that the rate of GMSL rise has been increasing and Sweet and others (2022) project that the rise in GMSL over the next 30 years will be as much as that over the past 100 years. The 2022 report notes a high level in confidence for their sea level rise scenarios over the next 30 years. Post 30 years the confidence level for sea levels is lower primarily because of uncertainty regarding some of the ice sheets in Greenland and Antarctica.  

GMSL is not simple and the sea level rise is not uniform around the planet. Some places will see greater sea level rise and others less. The 2017 report included an image of global sea level rise from 1992 to 2016 derived from satellite data measurements. 

 

Figure from Sweet and others (2017)

Global sea level has rises in an uneven manner due to currents, warm water expansion, and changes to gravity fields from more water in the oceans (the Earth's surface is flexible). The sea level also can vary due to cyclical climate patterns that move the ocean water around via wind and temperature patterns. I like to think that the ocean layer as having weather only slower and a bit less pronounced than the atmosphere. The image above also shows that on the Washington State coast the global sea level trend was near neutral for the 1992-2016 time period.

The 2022 report has an image with three plots showing global sea level rise along the coast of North America. 

Figure 2.1 from Sweet and others (2022) Regional sea level linear rates of rise (mm/year) from satellite altimetry over three different time periods: (a) 1993–2006, (b) 2007–2020, and (c) 1993–2020. Linear rates of change of relative sea level (ocean and land height changes) from tide gauges over the same time period are also shown (circles). 

For Washington State the 1993 to 2006 period the regional sea level rise was mostly neutral, but the more recent period of 2007 to 2020 shows that regional sea level on the Washington coast has increased as has the regional rates in most places around North America. 

The global and regional sea level increase is not a simple uniform rise. There is an added complexity: while regional sea level is changing, the land next to the sea is also changing in level. More on that on a future soon post.

Atmospheric Rivers reads and notes

Since northwest Washington State (and more so southwest British Columbia) are experiencing a series of atmospheric rivers (AR), I have been doing a bit of reading/catching up on the subject. On a professional level ARs paly a role in my work assessing geology risk so understanding ARs is important in assessing geology hazards. 

ARs have and continue to receive a lot of attention as they are the cause of much of the large flooding events of the west coastal watershed of North America and are also the source of much of the water in watersheds of the southern portions of the west coastal area. Due to the risk of large floods and the impact to reservoirs, there has and will likely be a continued interest in evaluation and understanding ARs. The most recent flooding in southwest BC and northwest Washington emphasized the importance of this issue. Further, ARs are expected to change with global warming -- there are numerous papers of modeling and climate simulations that indicate changes in ARs over past and present day.  

What follows are a few papers with my own notes and what I thought to be pertinent quotes from the papers themselves.   

Neiman and others (2011) focus on ARs impacts on 4 different western Washington watersheds, the Sauk, Green, Satsop and Queets. They identify some key attributes to ARs that produce floods. 

"ARs were responsible for all floods in these basins during the 30-yr period, even though not all ARs during that period generated flooding. Those ARs that produced flooding typically exhibited two or more of the following attributes: (i) the AR was optimally oriented for orographic precipitation enhancement in a given basin, (ii) the low-level onshore water vapor fluxes into the basin were quite strong, (iii) the AR stalled over the basin, (iv) the melting level was especially high, and/or (v) basin soils were already saturated prior to AR landfall."

The recent AR flooding in northwest Washington and southwest BC had essentially all of the above attributes. 

 A figure from Neiman and others (2011) illustrates the attributions for the basins they evaluated.

Conceptual representation of key atmospheric conditions associated with the top 10 annual peak daily flows observed in four watersheds in western Washington. (a) Offshore composite IWV analysis (cm; green shading >2.8 cm) based on the NARR for the Queets and Green Rivers. Washington State is shaded and labeled. (b) Overland composite low-level wind-flow direction (blue arrows) based on the NARR for the Green and Queets Rivers. See Fig. 3 for details on the base map. (c),(d) As in panels (a) and (b), except for the Sauk and Satsop Rivers and red arrows. (e) Composite NARR-based vertical profile information common to all four watersheds in the low-level onshore flow (bold arrow). The upper and lower horizontal dashed lines mark the observed and climatological melting levels, respectively (the climatological melting level is from Minder 2010). Gray shading represents the layer of weak moist static stability. The black curve depicts the water vapor flux profile.

Baek and Lora (2021) suggest that ARs intensity may increase sooner rather than later relative to other published papers. If their assessment holds true, changes to ARs will come sooner than most other modeling papers suggests:

"Here we use a series of coupled model experiments to show that there was little to no change in mean AR characteristics in 1920–2005 due to opposite but equal influences from industrial aerosols, which weaken ARs, and greenhouse gases (GHGs), which strengthen them. Despite little historical change, the simulations project steep intensification of ARs in the coming decades, including mean AR-driven precipitation increases of up to ~20 mm per month, as the influence of GHGs greatly outpaces that of industrial aerosols." 

Espinoza and others (2018) suggest that ARs will not be as frequent in the future, but may be much more impactful: 

"The projections indicate that while there will be ~10% fewer ARs in the future, the ARs will be ~25% longer, ~25% wider, and exhibit stronger integrated water vapor transports (IVTs) under RCP8.5.

Further works on field experiments, process studies, and model evaluation and improvement (e.g., Guan & Waliser, 2017; Hagos et al., 2015; Payne & Magnusdottir, 2015; Ralph et al., 2016; Wick et al., 2013) need to be undertaken to improve the model fidelity and reduce the uncertainty in the projections."

Gershunov and others (2017) consider the increased trend in AR to have already begun and project the increase trend will continue. They also note that the trend will not be uniform along the west coast:  

"Moreover, a long-term trend expressed broadly in stronger winter AR activity over the U.S. and Canadian west coast (weaker over Mexico) is associated with long-term warming of the western tropical Pacific; the latter SST trend has previously been identified in multiple observational data sets and explained by anthropogenic forcing [Wang et al., 2015]. Long-term precipitation changes over western North America have been very consistent with this trend. This broad increase in AR activity is corroborated by total seasonal IVT version of the analysis, where it is clearly associated with basin-scale ocean surface warming, as well as by a consistent increasing trend pattern in observed precipitation. These results suggest that the increase in IVT projected for the midlatitudes in response to global warming [Lavers et al., 2015] has been ongoing over at least the north Pacific, which calls for an investigation of the role of ARs in the projected enhancement of extreme precipitation over California and the Western U.S. [Polade et al., 2014] as well as a fresh investigation into observed changes already under way."

Rhodes and others (2020) project that the changes in total precipitation in the west of North America will be primarily the result of ARs 

"Changes in precipitation totals are due to a significant increase in AR (+260%) rather than non-AR (+7%) precipitation, largely through increases in the most intense category of AR events and a decrease in the interval between landfalling ARs."

Gershunov and others (2019) also project changes in precipitation specific the watersheds on the west coast. For the the Chehalis River:

"In fact, AR contributions increase in all precipitation bins, with the increases becoming greater at higher intensities, while non-AR precipitation contribution is projected to become more frequent in the drizzle and other low-intensity precipitation categories, and decreasing at higher intensities."

Dongyue and others (2019) did a broad overview of rain-on-snow, a possible contributor to AR flood events (see Neiman and others, 2011 above). Their assessment was not specific to ARs and covered all areas of the US subject to rain-on-snow. Cliff Mass cited this paper in a blog post suggesting that snow melt is a minor contributor to recent flooding after comments suggested snow melt was an additive factor to the recent flooding. However, despite that reference, Dongyue and others (2019) note:  

"It is also clear that a significant portion of floods that occur in basins that drain the west facing slopes of the Cascades and the Sierra Nevada are ROS related."

I do agree that for the recent AR event (November 14-15) rain was the source of the majority of the water in the floods, but even a relative minor snow melt component, say 10 percent, can push a river to a much more consequential flood event.

 Dongyue and others (2019) further note:

"Historically, the contribution of ROS to extreme runoff in the western United States has been greatest in midelevation areas (1,000 to 1,500 m); this “significant influence zone” will shift higher in the future (above 2,000 m). 

This elevation range matches many but not all Cascade watersheds.

The recent AR event in northwest Washington and southwest BC is a preview of what society should plan and prepare for as ARs become more intense with global warming.

Notes on Skagit and Nooksack Flood Levels

An atmospheric river  has been aimed at northwest Washington over the past few days and the rain continues today. A look at river level gages and predictions indicates some serious river flooding. But note too that many small streams have no flow gauges or predicted flood crests will flood as well.

The Skagit River has reached flood stage , but the current predicted flood crest at Mount Vernon will not arrive until tomorrow. The Skagit is a large river watershed and the peak flows take a while to get down to the delta area. Projections are for record flood levels at Mount Vernon.    

The much smaller Samish River also flows out onto the Skagit delta will peak faster with a record peak today. 

Both of these rivers flow out across broad low delta areas with portions of the deltas diked from tidal flooding. The Skagit has very large levees through Mount Vernon. But some over topping may take place. The Samish also has levees, but they will very likely be over topped. Once the delta floods the drainage out of the delta is restricted by the tidal levees -- all that water that spills out of the rivers then has to flow through drainage systems and tide gates.   

The Nooksack River began flooding yesterday. The Nooksack flooding is complicated. At Ferndale the projection is a moderate flood level. 

However, upstream at Cedarville the projection is potential record flood levels. 

Between Cedarville and Ferndale the river flood waters flood out of the Nooksack and into the Sumas River River (everson-sumas-overflow). Hence, the flood levels at Ferndale is somewhat diminished by water laving the Nooksack and flooding into the Sumas River. The border town of Sumas in the Sumas watershed began flooding yesterday.     

The Nooksack River has three forks that converge above Cedarville. This ads another complication to the Nooksack flooding because the timing of each forks peak discharge makes a big difference in the flooding downstream. There will be major flooding in the South Fork valley. 

  

Notes on Heatwave Global Warming Attribution

Phillips and others (2021) have taken a rapid assessment run at global warming attribution of the 2021 Pacific Northwest heat event. A summary of key points is provided at the beginning of the paper. Two points stand out:

The observed temperatures were so extreme that they lie far outside the range of historically observed temperatures. This makes it hard to quantify with confidence how rare the event was. In the most realistic statistical analysis the event is estimated to be about a 1 in 1000 year event in today’s climate.

This simply emphasizes what most long-term Pacific Northwest residences felt - this event was very far from what anyone expects for northwest summers. For those that experienced the event, you have a story to tell. But this was more than a remarkable event for the Pacific Northwest; Christopher Burt author of Extreme Weather stated “This is the most anomalous regional extreme heat event to occur anywhere on Earth since temperature records began. Nothing can compare.”   So for those that went through the event (I missed it), you can say you went through a world historic weather event.

There are two possible sources of this extreme jump in peak temperatures. The first is that this is a very low probability event, even in the current climate which already includes about 1.2°C of global warming -- the statistical equivalent of really bad luck, albeit aggravated by climate change. The second option is that nonlinear interactions in the climate have substantially increased the probability of such extreme heat, much beyond the gradual increase in heat extremes that has been observed up to now. We need to investigate the second possibility further, although we note the climate models do not show it. All numbers below assume that the heatwave was a very low probability event that was not caused by new nonlinearities. 

Under the first possible source, that the event was a very low probability event, global warming additive attribution pushes the temperature upward some amount more. Phillips and others (2021) note that the observed annual maximum daily temperatures in the Pacific Northwest trend is approximately 2 times the global temperature trend. So regardless of the event being rare, our heatwave temperatures have been trending upward at a greater rate than the global temperature trend as well as our local temperature trend.

Figure 4 b) Annual maximum of the index series with a 10-yr running mean (green line)

Burt noted in 2017 that Seattle has had 122 record high temperatures since 2010 compared to 19 record low temperatures and Salem has had 98 record highs compared to only 11 record lows.  

Another potential added source of heat is the trend of 500hPa height associated with a warming expanding atmosphere (Christidis and Stott ,2015). 

Phillips and others (2021) also suggest a source of added heat may be from persistent drought in the west leading to higher temperatures.

Given the circulation associated with major heatwaves in the Pacific Northwest, drought and enhanced heating in the southwest will be a contributing factor as hot air from that region descends into the lower elevation areas of eastern Washington and across the Cascades to the west side. 

Phillips and others (2021) suggest that global warming pushed the temperatures about 2°C warmer than they otherwise would have been. 

The other question or cause would be the potential that the heatwave was caused by a 'nonlinear' factor related to global warming. Phillips and others (2021) do not attribute this event to a nonlinear event such as a wavy stalled jet stream, but do give it a brief discussion and suggest further analysis. 'Stuck' jet streams or omega blocks are a point of some debate in climate science. 

I would note that this attribution paper was a bit narrow. John Pollack (HERE) notes that this event was preceded by two western US heatwaves of similar pattern, but to the south in June that set records including tying the all time high temperature in Palm Springs, CA of 123 F. Those events likely provided some additional heat charge to the third high pressure event centered in south British Columbia with southeast flow of air coming up from the southwest U.S into the Pacific Northwest. And the pattern of high pressure heatwaves of long duration is continuing. From the National Weather Service: The current forecast for Las Vegas is just below the all-time record of 117.  This is the fourth western US major/record breaking heatwave in the past month.

A Few Notes and Readings on the Heat Wave

I missed the heat event in Washington as I am out of the area. So I have no direct observations about the event. From afar it was really remarkable to follow this event as it developed. The weather models and projections were alarming and I will say it caused a level of concern for friends and family. I will also add that I have spent a fair bit of time in the Fraser River canyon and it is is painful to think about what has happened in Lytton.    

First of all, the weather prediction models were amazing. Models can be useful, but it really is remarkable when the models indicate something that has never happened and is an extremely rare event and the actual event happens as the models indicated.  

Phillippe Papin via twitter.com/pppapin/ lays out the antecedent event in the tropics and how the extreme heat would be generated. Note the post was June 23.  

There were a few statements made during the run up to and after the event that warrant repeating:

From the National Weather Service Seattle Office as the heat event was about to take place:  "As there is no previous occurrence of the event we're experiencing in the local climatological record, it is somewhat disconcerting to have no analogy to work with." --- National Weather Service, Seattle on June 27, 2021. 

This statement from Bob Henson and Jeff Masters clarifies what a big deal this heat event is: "Never in the century-plus history of world weather observation have so many all-time heat records fallen by such a large margin than in the past week’s historic heat wave in western North America. The only heat wave that compares is the great Dust Bowl heat wave of July 1936 in the U.S. Midwest and south-central Canada. But even that cannot compare to what happened in the Northwest U.S. and western Canada over the past week.", Bob Henson and Jeff Masters (worlds-most-extreme-heat-wave-in-modern-history)

Jeff Beradelli (Here) -- "To put climate extremes into perspective we measure against the average. The sigma is the standard deviation of a normal distribution of expected values. In this case the heat dome sigma max is 4.4 - that means it's outside of 99.99% of expected values or a 1/10,000+ chance.

 Bumbaco, Dello and Bond (2013) describe of how most heat waves develop in the Pacific Northwest and that description is consistent with this latest event. They note "Current research suggests that the frequency and duration of heat waves are expected to increase in much of the United States, and analysis of the heat events reveals that a significant, increasing trend in the frequency of the nighttime events is already occurring in the Pacific Northwest. A heat wave occurred in 2009 that set all-time-record maximum temperatures in many locations and ranked as the second strongest daytime event and the longest nighttime event in the record."

This chart shows that since the 2013 above described paper there have been a number of additional heat evets of 20+ above normal, and this event blew way past what took place in 2009.  

The attribution of this event to anthropogenic global warming (AGW) will be analyzed in detail. The attribution of AGW to extreme heat waves has been generally strong (Special Supplement to the Bulletin of the American Meteorological Society Vol. 102, No. 1, January 2021).

Diverse Commutes This Week

 Washington State does have a diverse landscapes. That was very evident on two very different morning commutes this past week. 

Start of the day with temperatures heading towards upper 90s. This area gets just over 6 inches of annual rain 

Note the hazy lower sky - smoke from a fire to the west. Based on the fire location I altered my route back home to avoid breathing the smoke.

The fire on Yakima fold belt ridges southwest of Ellensberg.

Buildings are hay storage facilities. The dry windy climate is excellent for high quality feed hay.

This fire brought some smoke to western Washington a couple days later when the overall air flow reversed and flowed from east to west. For the most part this summer has been a low smoke year in Washington State.  

Next morning a very different commute. Heading across the Puget Sound to the Olympic Peninsula. 

Winter Notes From the Skagit Delta and Spring Tulips

Winter is well over now. A quick sum up of this winter's weather in western Washington: September was very wet - so wet that on the Skagit and Samish Flats the potato harvest was not completed due to saturated fields that prevented harvest equipment from being able to operate. The rest of the fall reversed course including into December. It was not the typical days of rain and gloom but instead was mostly dry and mild. January made up for the dry fall with relentless rain that led to a fair uptick in shallow landslides. A brief week of cold spell followed with, at least at Samish, a string of snow storms that kept me home bound for a few days when the snow got above the front bumper. The rest of the late winter and spring was dry. 

A key to farming on the Skagit and Samish Flats is getting out on the fields. The early dry spell meant an early start to working the rich delta soils. It also meant upon my return from eastern Washington getting behind slow farm equipment on the road.    

The sloe pace of 10 miles per hour gave me a chance to enjoy the scenery including views of tulip fields.

Although the day was bit overcast the ground was warmed up enough to cause a distant field of red tulips to appear to levitate.

Tulips are a business. The above field had been harvested for cut flowers earlier in the day. Eventually the bulbs are harvested as well. Hope this will bring some brightness to our Covid times and the workers in these fields stay healthy. 

Adiabatic Heating and The Bear Who Stole the Chinook

A few messages suggested a bit more background on Snow Eater Wind would be useful. If there is a barometric pressure gradient across the mountains air will flow over the mountains and then descend down the other side. The air is a gas and will follow what is termed the Ideal gas law.  The simple equation is PV = NRT, where P = pressure, V = volume, N = amount of gas (moles), R = gas constant (a number value with an interesting history) and T = Temperature. Hence, if the pressure of the air is increased air will become warmer and if pressure decreases the air will become cooler; other aspects of the equation remaining equal and the gas behaves ideally. Of course there is more to this and that is why we have meteorologists.

Meteorologists use a term called dry adiabatic lapse rate and moist adiabatic lapse rate and  for how temperature will change within an air mass. When an air mass descends it will warm because the pressure is increasing. As an air mass descends it will warm at the dry adiabatic lapse rate which is approximately 5.5 degrees F for every 1,000 feet the air descends.

The strong east winds that reached Bellingham and Skagit County as well as the lower west slopes of the Cascade Range to the south were the result of a high pressure mound of air east of the Cascades with a low pressure off the coast of Washington. The high pressure air flowed towards the low pressure and as it descended it warmed at the dry adiabatic lapse rate. Even if the original air mass pulled over the mountains may have been cold, the increase pressure would cause it to warm substantially. The roughly 7,000-foot drop over the North Cascades Range would produce a warming of the descending air mass of 38.5 degrees F. So an air mass of say 10 degrees F would warm to 48 degrees F, about the temperature spike Bellingham had for a few hours last Wednesday evening.

Technically this is not a Chinook wind per meteorology, but the results are very similar and I would note the term Chinook wind is used more broadly by some and I do not know if the type of wind that descends east from the Cascades has been given a name.

Billy and I experienced our share of Chinook winds and he alerted me to this song by Jack Gladstone, a Blackfoot and former U of W Husky.       

Snow Eater Wind Comes to Northwest Washington

Down slope winds off of mountain ranges can have a pronounced impact on temperature. Long cold spells in central and eastern Washington will come to abrupt ends when storm systems from the west are strong enough to push across the Cascade Range. The descending air will scour out the pool of cold air but also the descending air warms rapidly causing a sharp jump in temperature. The wind is locally called a Chinook and the term is used widely in the interior northwest U.S. out to Montana and the plains of Alberta.

A similar phenomena took place last night in the lowlands of western Washington - only the wind direction was reversed. A low pressure off the coast to the west created a sharp pressure gradient from east to west across the Cascade Range. The result was a sharp temperature increase from the descending air.         

Bellingham temperature plot

In Bellingham the temperature jumped about 20 degrees in minutes. The temperature spike lasted for a few hours and when the descending winds eased, the temperature returned the low 20s.

A similar effect took place in the Skagit lowlands that I experienced first hand. I had to venture out to pick up Lisa at the train station in Mount Vernon. The wind was very hard from the east; high enough to cause some slipping on the icy roads as the car was pushed about, and formed numerous speed bumps of snow drifts. But on the return the temperature jumped from the low 30s to the mid 50s in less than 5 minutes.

The Blackfeet Indians called these events snow eaters. Indeed much of the snow was eaten away down from its deep layer by the warmish and dry wind before the temperature lowered to the 30s and the slow wet melt that has persisted all day. 

Klickitat River Delta

The Klickitat River discharges into the Columbia River just west of Lyle, Washington. The delta formed by the Kickitat is a busy place.   

The narrowing on the river at the delta attracts fishermen whenever fish are running. The high turbidity of the Klickitat is due to its glacial origin off of the east flank of Mount Adams, a 12,000-foot strato volcano. In the later summer the water in the river is dominated by glacial melt water. 

The delta also provides an excellent launching area for wind surfers.      

The Columbia Gorge is a windy place as it provides a gap between through the Cascade Range. During warm summer weather the heating on the east side of the mountains creates a strong pressure gradient through the gorge and weather systems coming in from Pacific also create strong pressure gradients through the gorge.

But note, the lack of wind mills. This section of the gorge is within a designated national scenic area and hence wind energy development is precluded in this area. Large wind farms are located to the east outside of the scenic area.   

The Cascade Range Defeats the Stratus

I have been traveling a fair bit. This has allowed me to have more of an opportunity to enjoy hot weather. Northwest Washington rarely reaches 90. My latest venture to hotter climates afforded a nice view of Mount Saint Helens.

Mount Saint Helens rising above the low stratus

The stratus forms in the cool air coming over the Pacific

On this day the stratus layer evaporates as it crests the Cascade Range

A fairly typical event in Washington summer weather

  

Western Red Cedar Die Back in Western Skagit County

Dead western red cedar

Kimberly Cauvel wrote a nice article on the die back of western red cedar in western Skagit County here: /warm-dry-summers-taking-toll-on-area-trees-plants.

Western Skagit County is partially within the rain shadow of the Olympic Range and hence a bit drier than some other parts of western Washington. Seabacher (2007) noted western red cedar die back on eastern Vancouver Island is similar dry sites.

Much of the die back I have observed in Western Skagit County has been on glacial marine drift soils near Bayview and and Samish Island (above picture). Many of these trees appear to have had previous stress as many of the trees have dead leads. But many now, such as the tree above, have completely died. The tree pictured above was one of six nearby cedars that have died within the past year or two. Within a quarter mile of this site are dozens more that have died.

Glacial marine drift soils in the area are silt and clay dominated. The silt and clay holds water and perched groundwater develops on these soils such that seasonal wetlands are common. However, the soils will become desiccated in the summer. A slight increase in overall temperature particularly in the spring and summer may be just enough to push the ability of some western red cedars to survive.   

Birch Bay Storm Surge Event Notes

Birch Bay in northwest Washington was the site of coastal flooding during the last storm system.



The flooding was in part the result of the initial low pressure system just off the west side of Vancouver Island. The low created pressure itself caused a sea level rise on the order of 1 foot above the astronomical tide levels. The location of the low off Vancouver Island also created winds that pushed water into the Strait of Juan de Fuca and Salish Sea. The local winds further enhanced the storm surge of tide levels. The local winds also were oriented to develop large waves in a bay that is otherwise rather calm.

The closest tide station with continuous measurements is just south of Birch Bay at Cherry Point. The storm surge at Cherry Point during the storm was 2.5 feet; a high surge for the Salish Sea.

The maximum storm surge coincided with the peak astronomical tide. I suspect that that the storm surge at Birch Bay was even higher due to local geometry of the shoreline and wind direction.

By comparison, the last big storm surge event at Cherry Point was in 2006.

The 2006 storm surge event also coincided with a high tide event and reached 12.5 feet. That event had essentially the same storm surge of 2.5 feet, but the astronomical tide level was 0.5 feet higher in 2006 versus 2018.

Birch Bay may have other issues that will drive erosion and flooding along the shore. The road along the bay is located on top of the upper berm of the beach. Sediment deposited on the road is removed and hence the berm remains at the same level. Sediment supply to the beach has also been disrupted by the cutting through the beach to build a marina on the north of the bay and by shoreline arming on the bluffs south of the beach. 

Eastern Washington Ice Fog and Riparian Forest on the Columbia

Much of eastern Washington is dry. Total precipitation is as low as 6 to 7 inches in the driest parts. However, winter is not necessarily sunny in these dry areas. The bowl-like shape of the Columbia Basin traps cold air that tends to stagnate as a blanket of chilly fog. The result can be days no sun.

Over the past week the fog was spotty as I meandered about on my various ventures. The temperatures were cold enough to brighten the landscape with the fog freezing on the plants.

No distant views on this stretch of the trip

Flocked trees at Verneta

The Columbia River is warm compared to the air and adds to the fog near Priest Rapids

The fog thinned near Mattawa and the orchard/vineyard windbreak trees provided a nice winter show 

The fog was limited to the lower Columbia Basin on this day and I broke free of the fog at Sentinel Gap 

Much warmer and bright north of the gap at a familiar line of trees along the river downstream of the old rail bridge. I wrote a report on this tree stand a while back. The evergreens are junipers. They as well as the other river front trees have become progressively thicker since. The tree stand is not "natural", but is the result of alteration of the flow regime on the river. The big yearly floods of the past are no more and hence the riparian areas are not as dynamic as there were in the past allowing trees to become established along the river side. The development of these riparian forest zones has created new ecosystems along the Columbia River.

Hole in the Clouds: Von Karman Vortex

Back in early February I observed spiral of low stratus clouds off the U.S. west coast. I put up a short note about it (swirling-hole-in-clouds).

Doing some random research on a favorite topic I came across this NASA image:

Holes in the stratus down wind of Tristan da Cunha

As a side note I have been fascinated by the South Atlantic island of Tristan da Cunha in part because I once had a map of the world completely covering on my wall and Tristan was right above the table I ate at - a remote island in the ocean demanding attention.

The hole in the clouds I observed is the same phenomenon and has a name - Von Karman vortex. And turns out that what I observed caught the attention of others and made the local news: https://weather.com/science/weather-explainers/news/2018-02-04-southern-california-von-karman-vortex