Measuring Amount of Precipitation in Snow

Reader Contribution by Bruce Mcelmurray
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Living in the mountains snowfall is not only essential but highly important to our safety and well being. Snow provides water for our deep wells, trees, plants, animals and shrubs. It also is needed to keep mountain lakes healthy and provide water needs for lower elevations. Once when I was learning to do our own plumbing a plumber told me I really only needed to know two things: one, water flows downhill and two, payday is on Friday. In early spring when the snow melts water percolates into the ground from higher elevations and some of that early melt bubbles up on our property and will migrate on down the mountain. We have two springs that flow all year long and several more that are transient. Occasionally it comes out of the ground so forcefully that it looks like a small fountain. One year it washed our driveway out because it surged out with so much force. When it runs so strong I usually take my gold catching sluice box and put it where the water runs through it and pick up a little placer gold coming from deep within the mountain.

Snow/Water Ratio

I have wondered over the years about the snow we receive each winter and how much actual moisture it produces for us. I have noticed as the snow gets deeper, 2-3 feet deep, that the snow becomes granular instead of soft and fluffy like new snow. I became curious as to which type of snow held the greatest amount of moisture. I took a jar (see photos) and collected 4” of the granular snow. I brought it inside and let it melt. I was surprised to find out that 4” of granular snow actually made 1.75 inches of water. Normal snow ratio is 10:1 or 10 inches of snow to 1 inch of water content. This first sample actually came out to 44% water content. As the days get warmer and it slowly starts to melt into the ground and then migrates down the mountain it will generate a considerable amount of needed annual water. Our average annual snowfall is 264” and therefore capable of producing substantial amounts of water.

Snow Shortfall

What I do know presently is that the two feet of granular snow we currently have that is waiting to melt is equal to 14” of water. That is far short from what our average is per winter and with a total accumulation of 85” of snow to date we will need another 179” in the next 90 days to achieve average. Those 85” have actually now condensed down to 24” of granular moisture holding snow. When living in the mountains we welcome snowfall for many reasons. One is for recreational use but the other reason is that we rely on the water content to keep our trees, meadows, wildflowers, grasses and even our weeds green and healthy. When it is dry we suffer from insect infestation to our trees and potential wildfire threats. Last winter we only received a total accumulation of 165” snow which is far below our average. Winter storms can produce any where from one inch to up to six feet (the most we have received at one time) of snow. For us here in the mountains there is still plenty of winter to catch up to our average accumulation.

Snow Equality

No experiment would be complete by itself if others were not conducted to compare. The first time I used granular snow that has been building up for months. The second experiment was with fresh snow. The granular snow is apparently where many flakes combine to make it into tiny ice crystals hence it would hold the combined condensed moisture of several flakes of snow. My interest in the volume of snow we receive is whether the 10:1 ratio of snow to moisture is always applicable. Accumulated snow clearly is not the same since it has been on the ground in ice crystal form for months. Therefore it would depend on which snow I actually tested to see if the ratio is accurate.

When living remotely in the mountains things like snow intrigue me perhaps because we have so much of it to deal with. Being intrigued is better than cussing and spitting while shoveling it for 7 months out of the year. I just imagine to myself that I’m moving vital moisture for later use. If cussing and spitting works for you in moving snow then I would have to say – knock yourself out. The one exception however is when it slides off the roof and goes down my collar. As I do the crazy dance I’m subject to expanding my vocabulary with “unfit for human ears” words when that happens. If we lived elsewhere, I would most likely be too busy to even give the snow much thought other than how long it would take me to clear it away so I could get to where I needed to be.

Living where we do and being dependent on moisture from the snow is important for us. As can be seen in the second photo 4”of fresh snow produced 3/8th inch of moisture while the line above that is the moisture content of granular snow. This tells me the ratio is pretty accurate and knowing that will help me plan future activities. What I do know for certain is that water runs down hill – a plumber told me so. Another wise man once told me if I wanted innocuous conversations to talk about personal experiences or the weather. If I wanted a good argument to talk about politics or religion. In case you haven’t noticed this topic is about weather. Two sayings by two wise men that sure work well for me.

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