Mt. Nusatsum

Mt. Nusatsum

Tuesday, December 15, 2009


No, I am not 'fraziled' by the weather, but thought I would look at the phenomena of "frazil ice" which is evident in any of the steep, bouldery and fast moving side streams in the Bella Coola Valley where you can now see the formation of frazil ice after a number of cold days.  Streams such as the Nookliklonnik, Snootli, Thorsen, Young Creek and others are all showing a large amount of frazil right now.   Ideal conditions for forming frazil are steep and bouldery streams where water is mixed and exposed to super cold air that results in ice crystals forming in suspension in the water.  These 'frazils' of ice are carried along and because they are small can attach themselves to the bottom and start forming 'anchor ice' which contrary to what you would expect, causes the stream to freeze from the bottom up.  Other frazils drift on down stream forming the pans of ice you see in the slower sections. With prolonged cold the stream can become all ice covered and slowly overflow, carrying more frazil around.

Extended periods of frazil are hard on fish spawn because of the extensive bottom ice that can form and fish can be affected by the ice crystals in the water. Fortunately our cold spells don't tend to last all winter.  In areas that they do, frazil can lead to trouble as water slowly flows and builds up ice and then water spills out somewhere where you least expect it.

Late last night a light snow whisked around the valley, but except for the Nusatsum Bridge 'snow hole' where there was about 3 cm, the rest of the valley barely received 1 cm.  Not a bad day though with the temperature tonight in the - 6 C range.  Grizzly

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