How do you do your SWE for CoCoRaHS, melt it or weighing method?

I add warm/hot water premeasured by tube and subtract it back out.
3 (37.5%)
I melt the snow in the outer cylinder by some means then pour into the tube.
3 (37.5%)
I use the weighing method with a precision scale.
2 (25%)
Other, no answer, don't measure snow for CoCoRaHS.
0 (0%)

Total Members Voted: 8

Voting closed: January 02, 2017, 09:03:55 AM

Author Topic: SWE Method of Snow Measurements  (Read 1018 times)

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Offline miraculon

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SWE Method of Snow Measurements
« on: December 19, 2016, 09:03:55 AM »
I began using the weighing method for CoCoRaHS snow SWE last year. It is a really big time saver for me. Previously, I was melting the snow in the outer cylinder in a special heater that I constructed, but after a few confirmation runs, I switched to weighing 100%.

I was curious about how other CoCoRaHSians are doing this task.

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Offline LFWX

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Re: SWE Method of Snow Measurements
« Reply #1 on: December 24, 2016, 01:01:33 AM »
Previously used the "add hot water" method and the "heat from outside" method.

Last year I purchase a digital scale, but we barely even had a winter here, maybe I will get to use it this year.
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Offline CNYWeather

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Re: SWE Method of Snow Measurements
« Reply #2 on: December 24, 2016, 06:04:04 AM »
I have a second tube. I switch them out each morning there is precip
and melt any snow or ice by putting the tube on my pellet stove.  :grin:

I did the tube in hot water but this isnt as messy.

Offline ValentineWeather

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Re: SWE Method of Snow Measurements
« Reply #3 on: December 24, 2016, 07:08:20 AM »
I have couple coco gauges so have experimented a little and decided to no longer mix warm liquid directly into outer cylinder with snow. I always came up short using this method. I believe this is least accurate of the 3 methods and promotes most evaporation.

My method is weight the outer cylinder down using something heavy like a pot lid, into sink of hot water 4-5" deep. Takes longer 10-30 minutes but what I feel works best. I also plug the cylinder hole preventing as much evaporation as possible.

I've also found using a heated tipping bucket (even professional model) between 35-40% of snow gets evaporated by the heater before having a chance to tip the tipper. This is a consistent number with the dry snow I get so makes it easy to calibrate for snowfall. I add a 37% offset and it it comes very close to actual SWE.