Thursday, November 25, 2021

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.

Monday, November 15, 2021

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. 

Sunday, November 14, 2021

Cedar Boughs

 Evaluating a valley in the Olympics earlier this fall I noted these cropped trees. 

The limbing was not for creating views through the forest, but was a partial harvest of the tree boughs for evergreen arrangements and/or wreaths. The trees in this case are western red cedar. And this was an allowed operation by the land owner. Evergreen foliage is a big business on the Olympic Peninsula and southwest Washington, and unfortunately some of that business is illegal harvesting. It is particularly problematic in young tree stands as the removal of branches and even the tips of the trees destroys the tree plantation. The very fact that the trees above were scaled and limbed (by hand) in the manner they were indicates the value of these products.  

Saturday, November 13, 2021

Chicken Eggs

Traveling to a field work site I came across one of the larger egg producers in Washington State. The packaging for the eggs notes that the chickens at this farm are free ranging. Agricultural friends have told me that the egg labeling is accurate. I got to see what a large scale free range chicken operation looks like. Thousands of chickens meandering through open grass fields.   

The farm is Wilcox Farms in the Nisqually River valley. They kindly allowed me access across the farm to assess a site saving me from a rather long bushwhack along rough river bottom land.

Last week I passes by another large egg operation. I observed no chickens at that facility which is consistent with the labeling on the egg packages.

Sunday, November 7, 2021

Political Sunday: Snake River Dam Editorials and Sports Radio Goes Political

Snake River Dams Opinion Pieces:

Over the years various newspapers across the Pacific Northwest have put out editorial opinions on the lower four dams on the Snake River and printed guest opinion columns (disclosure - I wrote a guest opinion piece for the Bellingham Herald on the Snake River dams 20 years ago). The Columbian out of Vancouver, Washington published an editorial on the lower four dams (in-our-view-new-approach-is-needed-to-save-iconic-salmon). The editorial suggests breaching the dams "warrants serious consideration". The Columbian included a quote from another newspaper editorial from the Walla Walla Union Bulletin. Part of the quote stated "The water from a free-flowing Snake would flood farms, roadways, homes and even cities." 

Since the initial Walla Walla Union Bulletin editorial, the Union Bulletin corrected the Editorial and has a correction statement at the end stating "The Snake River dams do not provide flood control as previously stated."  

My take-away is that the Columbia Editors do not have a good understanding of the lower Snake River dams, otherwise they would have readily noted that the Walla Walla Union Bulletin statement about flooding made no sense. The Columbian error is somewhat forgivable; the Snake River is far upstream from Vancouver, Washington and one might assume that the nearby by Walla Walla paper would have a better understanding of the lower Snake River. Alas proximity to the dams may be a hinderance to understanding them, and the Union Bulletin editors credibility on this issue should be greatly diminished.    

Fall Back:

Note - I live just a bit south of the 49th parallel and pretty far west in the time zone.  

In my work I drive a fair bit to field sites. I listen to NPR, CBC and sports radio depending on where I am and the time of day or evening. The sports radio folks (KIRO) are generally pretty good at navigating through that political wickets. One of the conversations I heard on sports radio this past week was introduced as a political subject that all red and blue folks could support: a proposed bipartisan bill to allow states to remain on daylight savings sponsored by Washington Senator Patty Murray and Florida Senator Marco Rubio. The radio host was fully supportive of the bill. I support it as well. 

My rationale is that every fall I ease into getting up in the dark as the days grow shorter and sunrise slowly moves later into the morning. By the end of October I am getting up in complete darkness. I am not a fan of getting up in complete darkness, but I got used to it. With falling back an hour I have to restart the process or simply get up earlier (the same time by ignoring the clock all together). All in all getting up in the dark in the winter is not that big of a deal, but the sudden darkness at 5:00 pm is the part of the time switch I find to be very undesirable, and as the winter moves on, the late darkness moves to 4:00. I am on the west side of the time zone - it is even worse for those on the east side. 

Saturday, November 6, 2021

Debris Flows, Logging and Marbled Murrlets - Lake Cavanaugh

Lake Cavanaugh is located within the northwest Cascades near the southern Edge of Skagit County. The 2.75 mile long lake was formed by continental glacial ice that flowed eastward from the northern portions of the Puget ice lobe into the North Cascades. 

Lidar bare earth imagery of Lake Cavanaugh area

Blues arrows indicate ice flow direction with the arrow on the left being the main flow path of the Puget ice lobe and the blue arrow across the top indicating the ice flow from the Puget lobe up into the North Cascades. 

Lake Cavanaugh may have been an area of weaker fractured rock as it is aligned with the Darrington-Devils Mountain Fault zone.   

The south shore area of the lake consists or a series of alluvial fans associated with steep creek drainages coming off the north side of Frailey Mountain. Frailey Mountain is a steep ridge that rises about 2,000 feet above the lake. The bedrock on the mountain is mostly metamorphosed ocean floor basalts of the Eastern Melange Belt, a tectonic terrain. Sandstone and conglomerate of the Oligocene age Bolson Creek Formation underlies some of the mountain as well and there are areas of glacial sediment on the lower slopes.

Due to the steep slopes and narrow drainages the small creeks on Frailey Mounatin are subject to periodic debris flows.

Debris flow on one of the unnamed creeks in 2016.
There are some policy issues associated with these creeks but that will be another post. 

Lake Cavanaugh area was heavy logged in the past.  Bob and I came across this stump while heading up the slope to assess a potential debris flow source area.

The 1941 aerial image looks a lot like a lidar bare earth image. The clear cut logging throughout the area was very intense.   

Note that there was a stand of trees left on some of the steeper upper slopes (but not the ridge line) in the 1941aerial. As the forest grew back the old trees are still evident in 1974 aerial. 


They are not as apparent in the 2017 aerial, but logging in the area has started up again as the second growth is now merchantable and logging in the area has been intensive over the past 10 to 15 years. 

2017 - old tree stand circled in red

But the old trees remain. This remnant stand of old trees provides nesting habitat for marbled murrelet, an endangered sea bird that nests within old forest stands. A buffer around this habitat area is required for forest practices (proposed harvest). An added benefit is that bird's nesting presence and protection also reduces the potential for the very steep slopes from being damaged by tree harvest and has limited some of the recent proposed harvest on the north slope of Frailey Mountain.   

Thursday, November 4, 2021

Cascade River Valley and Remembering Scott

I had a venture up the Cascade River in the North Cascades. The Cascade River is a tributary river to the Skagit River. The river was flowing hard through a bedrock section of the canyon from the parade of mild temperature storms that have passed through over the last week, but given the high altitude of much of the watershed it was not at flood levels. 

During my traverse I came across this boulder that had recently landed in a patch of sword fern and had a fresh chip on the surface of the rock.

Looking up the slope did not reveal much as to the source of the rock.

However, this area of the Cascade River is in a deep valley with steep valley walls rising 4,000 feet from the the river. My guess is the rock derived from a band of steep exposed boulder rich glacial sediments about 600 feet up the slope.

All in all I got very wet ploughing through ferns and brush in a forest of western hemlock, western red cedar and Douglas fir.

Heading out I was struck by the splash of yellow gold of a cottonwood amongst the evergreens.

The splash of color reminded me of a past fall trip up the Cascade River valley after a good summer of field work in and above the Cascade River valley.  I vividly remember the fall colors of that trip and always associate that trip with sadness and loss but also some joy. The brightness of those remembered colors as well as the bright cottonwood tree I saw on this day remind me of the brightness of Scott. I always associate him with the Cascade River valley in the fall even though he never saw it.

Tuesday, November 2, 2021

Mount Baker Steam before the Rain

 Before the latest weather front moved in I had a short notice/time critical job on Orcas Island. This time of year I can push back departure to the 7:30 AM boat instead of the 5:30 AM boat since it is still dark when the 5:30 boat arrives on Orcas. The ferry schedule has been tweaked a bit due to recent staff shortages related to COVID. 

Waiting at the dock I had a nice view of the early light and Mount Baker. With frosty temperatures and moist air a pretty good steam plume was emitting from Sherman Crater on the south side of the mountain. 

Mount Baker with Twin Sisters Range on the right


Saturday, October 30, 2021

Pine Creek Loses some of its Forest


Malden Post Office before the fire

Attribution of a single wildfire event to global warming is confounded by lots of other factors. The Malden area and Pine Creek valley are located in a climate edge area where pine forests meet grass lands (and now dry land wheat fields) in a mosaic landscape. Pine Valley where Malden is located was already in a fire prone area. Every summer the area becomes dry enough to burn with the grasses and brush being susceptible for a longer period and the trees for a shorter period. Towards the southwest that length of time becomes longer and to the north and east the length of time is shorter. Pine Valley is in a boundary area just moist enough that tree killing fires have been infrequent enough such that the valley has significant forest stands. 

With warmer average temperatures the length of time the area is susceptible to fire is now longer. But other factors can increase fire risk - years of fire suppression and changes to land use also alter the fire risk and how a fire will behave. With lots of roads, fires in Pine Valley could be readily suppressed and put out as long as fire weather conditions were not severe. Land use changes also play a role. Over time the forested areas began to encroach into the Malden town site.

The weather event associated with this fire included very high winds associated with an Arctic cold front that surged across the area from the northeast. The high winds had followed several days of at or near record daily highs in the region. The weather set up and fire risk was predicted several days before it took place (Inland Northwest Weather.blogspot). The same weather event was also associated with a much large fire that burned over 60 miles in the Okanogan Valley as well as the very intense wildfires on the west slopes of the Oregon Cascades.   

Pre and post fire aerial images show that a fair bit of the forests that were in the Pine Creek valley burned during the fire. 

Malden 1954

Malden 2017

Malden 2021

Northeast of Malden 2017

Northeast of Malden 2021

Pine City 2017

Pine City 2021

Sunday, October 10, 2021

Malden, Washington Notes: Ice Age Flood Route

A bit over a year ago a wildfire burned much of Malden, Washington. Due to the extent of the destruction, the already tenuous economy of the small town and the very delayed National Major Disaster Declaration by the President, there have been follow up stories and takes on the fire and the aftermath ( Northwest Public Radio and Spokesman Review as well as Spokane area TV stations have continued to report on the town's effort at recovery.  

Malden Post Office before the fire

Malden is a bit off the usual routes; hence, I thought a little background on the landscape of Malden and the vicinity would be of use. I passed through Malden about a month before the fire and also on a trip to Rock Creek and Bonnie Lake (bonnie-lake-precambrian-schist). On that earlier trip I paused at the Post office (above picture). 

Malden is located in Pine Creek valley in the norther part of the Palouse. J Harlen Bretz (1923) recognized that the Pine Creek valley was a pre existing valley that was further eroded by ice age floods, "The valley during this episode in its history was but a channel. The glacial stream filled it from side to side for a depth of tens of feet. This is shown a few miles above Malden, where the stream flooded over a low shoulder of basalt, cutting a channel in the rock at least 40 feet deep, though the main valley alongside was a wide open and received gravel deposits." 

Map of Spokane Flood routes from Bretz (1925)

Flood water spillway from upper Latah Creek into the North Fork of Pine Creek (Bretz, 1923)

The ice age floods that Bretz was describing were the result of water spilling over from Latah Creek. The Okanogan ice lobe dammed the Columbia River forming glacial Lake Columbia in the backed up the Columbia River. The lake extended up the Spokane River and Latah Creek, a tributary stream to the Spokane River. When the ice dam at that formed ice age Lake Missoula collapsed, the flood waters surged out of the rapidly draining lake and into the Spokane area and into Lake Columbia. The sudden influx of a massive surge of water resulted in Lake Columbia overtopping at numerous low divides to the south. One big spill way is the Cheney-Palouse scabland tract southwest of Spokane. Interstate 90 passes through part of the tract. But some water backed up Latah Creek and spilled over a divide into the Pine Creek Valley.  

DEM of spillway from Latah Creek into Pine Creek

The ice age flood features in Pine Creek are a bit more subtle than the raw wide stripping of soil that took place in the very broad Cheney-Palouse route. But the features were noticeable to Bretz and are not consistent with the other valleys that were not flood routes that pass through the Palouse landscape. 

Another factor that softens the flood features in the Pine Creek Valley is that this flood route has a bit wetter climate than those to the west and the valley has more areas of pine -- hence the name Pine Creek. More on that on a future post.    

Wednesday, September 8, 2021

Pyrite in the Gravel

One of the sources of crushed gravel in Skagit County is a rock quarry. The quarry has mined large blocks of rock for levy projects, but the process of breaking the large intact blocks of rocks creates smaller rock. Hence a side product is angular crushed rock gravel for driveways and parking areas. The angular rock along with the fines within the crushed material forms a hard drive and parking surface. 

Crushed rock gravel parking area

Walking across one of these driveway areas on a moonlit night I noted remarkably bright spots in the gravel. My geology brain clicked in and I recalled the likely source of the gravel being a rock quarry excavated into some altered ocean floor igneous gabbro. The ocean floor rocks are a Jurassic age accreted terrain slab of ocean floor. Hot fluids flowing through and old ocean floor precipitated minerals. The bright spots I was seeing in the gravel was moonlight reflecting off of the very smooth surfaces of cubic pyrite minerals.       

A larger pyrite mineral - most are much smaller
I spotted this during the day when a very bright reflection struck my eye 

Pyrite is an iron sulfide mineral and is pretty common secondary mineral. Its breakdown via weathering in pyrite rich crushed mining tailings is a source of acid mine drainage. Its presence in some limestone deposits or the rock aggregates mixed into concrete is detrimental as the pyrite breaks down the sulfur released will form acids that will damage wiring, pipes or other metal in the concrete and can also form hydrogen sulfide foul odors.  


Tuesday, September 7, 2021

Ground Wasp Hazard Season

Field work hazards vary depending on where one is working and the time of year. In September in western Washington as well as elsewhere a hazard that I try to be alert for is ground wasp nests. 

Yellowjacket nest

The life cycle of the wasps is such that the nests become very large in late summer and the nest becomes populated with adult wasps that will readily defend the nest. Fortunately the wasps rarely sting when passing near the nest, but accidently stepping into or on a nest in late summer is a hazard.

I managed to avoid stepping into any nests last summer and thus far have a avoided doing so this late summer. Last week a client helpfully alerted me to a nest along a survey path cut through the brush prior to my field venture. I noted the small fast flying wasps near the nest shown above before spotting the entrance. 

My last encounter with stepping into a nest was on a very steep slope. The usual fast escape via running was impeded by the slope conditions which meant I had to crawl up the steep slope as fast as I could and likely further disturbed the nest as I began my escape. Once I reached the top of the slope, I was able to run, but continued to be stung. The next step was to shed my shirt and pants as fast as I could. Wasps release odors when they sting which stimulates additional stings and additional wasps to attack. My car was not far away and I had extra clothes (a typical habit as I often get wet doing field work). Even a half hour after my encounter there were still wasps stinging my dropped shirt.  


Wednesday, August 18, 2021

A Smoke Eclipse from the Schneider Spring Fire

I had a couple of central Washington projects and was relieved that the approaching cool front cleared the smoke away. The western air flow was evident as I approached the Columbia River gorge from the high plains of central Oregon.  

Lenticular clouds formed downwind of Mount Adams

However, the clearing of the stagnant air and smoke does not mean the fires are not still active. The Schneider Springs Fire (HERE) created a huge plume of smoke and cloud.

Plume of smoke and cloud above Schneider Springs Fire viewed from Yakima

In the Yakima Canyon between Selah and Ellensburg the plume of smoke passing overhead eclipsed the sunlight cooling temperatures in the canyon. 

North end of the Yakima Canyon with the Stewart Range in the distance and thick smoke overhead 

Dim evening like light south of Ellensburg

Smoke plume downwind darkening the Wenatchee Mountains

View to the west from Highway 10 northwest of Ellensburg

About half way between Ellensburg and Cle Elum I got back into the sun. 

Smoke plume and wind turbines northwest of Ellensburg

It was nice to have the smoke pass over and not breath it. There was some ash fall of white burnt fir needles while I was working in the Yakima Canyon, but no smoke, no hot sun and temperatures in the mid 80s made the work a lot easier than expected.

Thursday, August 12, 2021

Back From Halle (Saale)

I returned from a two month break. I did some remote work while gone, but am now back on field work and follow up writing ventures. I appreciated the support of my associates at Stratum Group that worked more than diligently in my extended absence as well as dealing with the issues of working in and through the time of covid and the preparations for changes in Stratum Group.  

For two months one of my views in Halle (Saale) was this wall across the street from where I was staying. I sat in a chair at the window and contemplated the odd assortment of rock blocks and obvious multiple periods of window openings. 

The building is old by the Washington State standards that I am used to. As best as I was able to piece together the history, the initial structure dated back to the 1200s, but it may be even older. I suspect it has had multiple periods of use and vacancy - pictures from the 1980s showed that the roof was missing. An associated building had been badly damaged by one of Napoleon's armies. 

The rock blocks are mostly local volcanic sandstone and volcanic rocks of Permian age. 

Geology is the basis of Halle's history; the Market Square Fault cuts through the city and that fault caused salt water springs to issue from the ground on the west side of the city. The salt was a very valuable commodity. The fault is given credit in the main square of the city next to the drinking fountain. 

The English side of the marker made my translation easy

As noted on the marker salt was utilized from the site at least 5,000 years ago. Approximately 20 miles to the west there is a Paleolithic site that dates back 400,000 years. People were here for a long time compared to my homeland in Washington. 

I returned home this last week with only a brief view of scenery on the flight back as most of the flight was over clouds.

Near to coast of Greenland

I miss my night shift and walk-about companion during my stay in Halle (Salle).  

At the river lock on one of many walk-about adventures