Saturday, April 22, 2017

So yes, after we managed to get out yesterday in a break between rain events, rain began once again on our return home from our daily ravine walk. The forest has an amazing capacity to absorb water, but even it has its limits. The deep winter freeze-up of the forest floor has finally been released to thaw, and the absorptive capacity of the forest thus has increased. Even so, there are numerous pooled areas in the forest making it resemble in part, a mini-bayou, a mess of swampy places where it is best to avoid venturing.


For the most part the trails remain accessible, although very mucky. The landscape looks dreary, but that is normal for this time of year when colour tends to be on the dark scale of the spectrum, all the more so when heavily overcast skies prevail. And the skies have been heavily overcast, and they have also emptied their contents copiously on the environment below. Causing flooding in low-lying areas and consternation when entire streets come under water.


For the forested ravine that we so much depend upon for our leisure exercise and exposure to nature that we so much value, all that excess moisture -- and this year it truly is 'excess' -- causes a natural phenomenon to occur that also comes into play when an earthquake -- to which this area is also inclined -- occurs. The soil base, Leda clay and sand, is affected under these unusual weather circumstances.



The base of the forest floor and deep within it becomes denatured in a sense, as the Led clay, completely saturated, becomes dangerously unstable. It has a tendency to liquefy, as it were, to completely lose its cohesiveness, and to disintegrate, sliding away, taking with it whatever stands upon it, in a huge slump resembling a miniature landslide.



When we first entered the ravine for our walk yesterday we noted immediately that to our right, at street level, the hillsides bordering and back of the homes on that side of the street had been involved in ongoing slumps, as a result of the excess of rain we've been exposed to. Trees leaned over here and there, having slipped from their moorings, on the cusp of falling into the ravine below. We knew a large slump had occurred further to the right a few days back but hadn't ventured to check it out, after being informed by neighbours whose houses are located down the street from ours.



An hour later, almost through our daily circuit in the ravine and again close to that area, we became aware of a sliding rumble, and the accompanying crack of trees. The sound arrested both us and our little dogs who found it alarming. It was indeed fascinating to hear, and it repeated several times. This time we ventured closer to where the slumps were occurring, hiking up a coll between two valleys in the ravine, on one side looking over to the hillside behind the houses where the slides were occurring. And we saw quite a mess.



The clay had separated, and huge areas of sloping forest had descended into the ravine below, some of it landing in the creek, which suddenly found itself blocked off from its normal flow pattern. Water always does find its way eventually, and further downstream we had earlier noted the widening of the stream, deep with mud-infiltrated flow. It seems that the inundated Leda clay will continue to deteriorate as long as the rains persist, and slowly alter the geology of that portion of the ravine.


The assumption is that what is occurring there, behind the street we live on, is also occurring elsewhere in the quite lengthy forested ravine, where the layout of the landscape is similar to the area close to us. Over the decades we have seen previous such instances of land collapsing from hillsides into the valleys below in various parts of the ravine. The circumstances of the elements collude to make landscape alterations that we feel are significant, but to which occurrence nature merely nods.



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