I've recently gotten a remote weather station working at my folks' house in the eastern Sierra, around 8,000 feet. I was looking for a way to create an automatic snow gauge, and found on one site where an ultrasonic device like the one Parallax makes, can be pointed straight down from up above to measure the snow depth. Here's the device displayed, but it's $850!
I know the Parallax sensor (far less expensive) measures up to 128", or 10.67 feet (sufficient in most years, but I know it's gotten deeper than that on occasion).
Still, the specs list its minimum operating temperature as 32F, which would present a problem. Has anyone else tried this or a different method to measure snow depth? Thanks.
(possibly related)
I recall there was on the old forum a discuzsion about a rain gauge witb some heating element so that after snow the amount could be measured. 10mm of snow == 1mm water approx.
(measuring snowdepth)
Be aware that the speed of sound differs with temperature and humidity so you need to calibrate the lookup table according to the temperature.
I recall there was on the old forum a discuzsion about a rain gauge witb some heating element...
But, OP wants to measure snow depth, not amount of snowfall.
OP, is there power where you would mount the sensor? If so, a small lightbulb in an insulated box with the sensor should keep the temp. above freezing. Size the lightbulb so that it does.
I added some context to improve readability of my response above.
But, OP wants to measure snow depth, not amount of snowfall.
The reason I mention measuring snowfall is that it is an indirect measurement of snowdepth in theory: snowDepth = snowDepth + snowFall;
Indirect measurement might be prefered as snow often gets distributed unevenly due to the wind etc.
In practice there is a correction factor due to melting (snow -> water) and sublimation (snow -> watervapor) of the snow. This correction factor depends highly on the temperature and wind.
The reason I mention measuring snowfall is that it is an indirect measurement of snowdepth in theory: snowDepth = snowDepth + snowFall;
What about compaction?
yes compaction is another cause. compaction due to weight (height/depth) of the snow itself but also compaction due to temperature (a bit melting and freezing again)
So the formula should become snowDepth = (snowDepth + snowFall) * factor; // factor = 0..1.0
at least the (org) formula gives the upper limit of the snowDepth.
*as my quote states "In theory there is no difference between theory and practice, however in practice there is ..." maybe to be changed to "there are many...." *
How about using a simple stick, with optical sensors (or, since rise/fall time doesn't matter, a bunch of cheap LEDs) mounted in 1 inch intervals? 5 Sensors in the dark = 5 inches of snow. I used a similar setup to let me know when our sump-pump tanks were getting ready to overflow (in the event of a power outage during a rain storm, or a failed pump).
Thanks all for good suggestions. Paul, I think you're right that a small light bulb would do the trick. Perhaps inside a small steel box with two holes'pointing straight down for the parallax sensor. I have put in an email to Parallax to ask what would be the effects of extreme cold on the device. As for accuracy of the measurement, it's an area where snow will easily compact and not drift much, and I was actually worried that 10 feet range wouldn't be enough because of the amount of snow we get there. I am interested in how the density of snow would affect the sonar's accuracy.
If you want to see the output of my weather station, visit http://bakguild.org/weather_read.php
Please note, however, that the wind speed isn't working just yet.
Just a quick update on this topic - Parallax says the PING device won't work on snow because of the texture. I might try it this winter just to find out. I'm not sure I completely believe this because all surfaces have some kind of texture and yet reflect sound energy waves. Well, a few more months and I'll get to test it.
Despite the age of this thread I still think this info is useful to the community:
I have tried to measure snow depth with a HC-SR04 ultra sonic sensor, and can confirm that it does not work. I tried with three different snow types (powder, slush, mixed) and none of them worked, i.e. the distance measurement was random and could not be calibrated. I will instead try an optical sensor.
AndreasNielsen:
Despite the age of this thread I still think this info is useful to the community:
I have tried to measure snow depth with a HC-SR04 ultra sonic sensor, and can confirm that it does not work. I tried with three different snow types (powder, slush, mixed) and none of them worked, i.e. the distance measurement was random and could not be calibrated. I will instead try an optical sensor.
The problem is not reflection because of surface texture, but selective absorption of the sound. The dryer and fluffier the snow is, the more absorbent it is.
Hello, if anyone still interested in this topic, I think you couldn't measure with HC-SR04 because you didn't considered the temperature and the speed of sound compensation. Here how I did it:
