Wednesday 11 January 2012

Snow survey can be tough

Snow lysimeter at the tributary site (elev. 140m)

Now sometimes snow survey can be a piece of cake. If the snowpack is not frozen hard, if the air temperature is just above freezing, if the sun is even shining, then for sure it can be one of the most pleasant things to be doing on a winter's day. Especially if the snow is quite deep, say around 2 metres, then it can be immensely satisfying taking your sample core of snow and weighing up the amount of water that will be released in the coming spring to irrigate the paddy fields and put your dinner on the table so to speak.

But the trouble with days like today is that with the sub-zero temperatures, your snow core freezes inside the sample tube, and no matter how hard you scrape, shake and prod, you just can't get the sampler clean for the next sample. It's immensely frustrating and can leave you in quite a bad temper. Maritime snowpacks will often contain a little moisture, especially at the base where you have ground heat slowly melting the snow, and it will instantly freeze to the aluminium sampler when you extract your snow core.

Still, my two students persevered and completed the survey as best they could at the tributary site, while I serviced the snow lysimeter and zipped up into the mountains a bit further to change the battery on the logger measuring spring water temperature. We also charged the winter storage gauge at the site, before brewing up hot coffee for lunch using the local stream water - delicious!

Snow survey (larch site): depth 69cm, SWE 20cm, density 0.29.

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