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Question: anyone working on dataloggers for snow depth?

MadTinker is asking a question about general: Follow this topic

by MadTinker | January 24, 2020 21:14 | #22398


There are a number of technologies available for measuring snow depth. I'm currently using a snow board (sorta like a bricklayer cement hod). There are various snow pillow technologies (pressure sensors under perforated plates) and also a sensor from Campbell that measures (I think) the distance from the ground to the top of the snow via a change in the electrostatic charge (?). I live in the SW Rockies and snowpack is a critical environmental metric. FWIW - my last project was wiped out by unexpected, very extreme snowpack. Anyone with sensor ideas that I could incorporate into a data logger? [I think a sonar approach would be pretty cool... but no experience in that area.] Thoughts or ideas? Dave



11 Comments

I think a laser rangefinder might work well for this. Put it on a pole and point it downward to measure the distance from the rangefinder to the snow surface below (like I did to measure water depth). The cheap sensors have a range of only one meter, but if that is not enough you can mount a second sensor on the pole two meters above the ground, and so on. A single Arduino can record data from all the sensors. During blizzards the data will be very noisy, but then you also have a record of when it was snowing. Total cost for parts to measure up to 2 m of snow depth for all winter on batteries is about $30.00.

Chris

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This post got me thinking weather it's possible to use the kind of technology laser range finders use, but at a wavelength that snow is invisible to. Some Google sleuthing reveals that snow doesn't reflect infrared very well so that might be a starting point. All those things really do is send a laser pulse and take a time-of-flight measurement (using a processor faster than the speed of light!) to give a distance. If a laser diode has the right wavelength, it's totally doable.

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I tried one of those little six dollar laser rangefinders (vl53lox) for measuring distance to snow. Those rangefinders don't work at all in sunlight because the laser is too weak and the sensor is saturated with NIR light from the sun. It works fine at night. I tried it on two different snow surfaces: an old packed surface and freshly fallen snow. Both gave reliable results although possibly more noisy than a solid surface. So I now have a snow gauge in the backyard sending the results to my phone via Blynk.

20200201-0.png

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Thanks Chris, unfortunately we generally have sunny weather so a laser is generally out. In addition, last year we rec'd 4.14m (163") of snow, with about 2m sticking around all winter. Granted that's on the high side and resulted in washing out all my other stream monitoring projects, it's still something I need to consider. I'm currently looking at a sonar unit with humidity and temperature compensation. I'll post more when I've made some progress. (and I'll have to check on Blynk!) Dave


The sunlight is not an issue. For a winter-long monitoring goal, a few measurements every day are plenty, and those can be taken at night. With the unit powered off all day long, the batteries will last a long time.

Stacking a few sensors on a pole, one every 1.3 meters, should be a reasonable solution. The program running the thing can even read the data and output a single snow depth result.

Chris


The U.S. Maintains a snotel (snow telemetry) network. These are stations that monitor the snow depth and then forward that data, daily, by means of meteor scatter. I couldn't find a description of how the sensors work, but it might be a good place to start. Maybe send the contact an email after reading up on snotel.


SNOTEL uses snow pillows which are devices about 3m x 3m, that sit on the ground and measure the hydrostatic pressure of the snow that falls on them. They have been around since the 1960s. There are 11 (traditional) SNOTEL sites at various, remote, locations around our area and I'm very familiar with them. As a data point, modern alternatives to snow pillows cost in the neighborhood $17K. Last winter I used a Weaverboard and I misjudged the length of the stick that would be needed and eventually had to replace it.


You have a much better idea in this field than I do. My apologies for any offense I may have caused. Good luck.


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The Arduino snow depth gauge seems to produce good data. It is an ESP8266 and laser rangefinder I2C sensor ($9 total cost). As expected data collected during the day is useless noise, but data collected at night is very good. There is still noise at night, but it limits precision by only about 1 cm.

The graph below records a two-day snow storm which increased snow depth by 20 cm. During the subsequent two days the snow pack settled and depth decreased.

Snow2-2-9.JPG

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Thanks Chris, unfortunately we generally have sunny weather so a laser is generally out. In addition, last year we rec'd 4.14m (163") of snow, with about 2m sticking around all winter. Granted that's on the high side and resulted in washing out all my other stream monitoring projects, it's still something I need to consider. I'm currently looking at a sonar unit with humidity and temperature compensation.

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