A SNOTEL Station in summer
I love SNOTEL. On the right day, I check it more often than Drew Tabke checks the TGR forum (okay, I’m exaggerating, I don’t check it that much). The point is, SNOTEL is not only a great tool for backcountry users, it’s also a great distraction from the monotony of daily computer work. Also, you can use it to call out ski areas when they reports 30” overnight, when the SNOTEL at the resort reports only 14” (cough…Alta….cough). Anyway, for those not familiar with SNOTEL, here’s an overview of what it is and how to use it.
Managed by the USDA, SNOTEL is a series of sensors that manage snow pack information in remote locations where access on a regular basis is difficult or impossible. The intended purpose of the sites is to provide real time snow pack information, from which information about the condition of the watershed can be derived (i.e. percentage of normal). From this, use of water management decisions can be made; hence it’s overseen by the USDA. However, for backcountry users it’s an incredible tool for getting unbiased information about snow conditions in the backcountry. Much like surfers can use information from nautical buoys to predict swell characteristics, skiers can use SNOTEL to assess snow pack and storm characteristics.
I should note here that although it is an incredible tool, it’s also very ROUGH information about the snow pack. Obviously, by no means is it a substitute for normal backcountry safety protocol. It can help you decide where to go, but once you’re there, you need to make your own decisions.
How SNOTEL works:
The measurement of temperature is pretty straightforward. Snow water equivalent and snow depth- factors that are fairly important to your backcountry decision- are a little more complicated. Snow water equivalent is measured by assessing the weight of snow that falls on a 4’ x 5’ “pillow.” Pressure sensors beneath the pillows calculate the snow-water equivalent, based on the pressure exerted on the sensors from the weight of the snow. Snow depth is calculated by sonic sensor. Basically, a sensor that measures the distance from a set height to the ground- the shorter the distance, the more snow there is.
Using SNOTEL info:
Take the last 24-hour period from the Togwotee Pass Sensor:
I cropped this photo from roughly when the storm began yesterday morning. What can you tell from this?
The storm came in warm-to-cold, with quite a bit of precipitation (almost 2″ of water content). The temperatures obviously tell you this but, more importantly, the snow water equivalent and snow depth tell you what’s going on within the storm cycle- about an inch of water content and only eight or nine inches of snow in the first 12-hour period (0900-2100). Then, temperatures drop and snow water equivalent and snow depth increase- but at a different rate. From 2200 to 0700 roughly the same amount of snow falls as in the first period, but with 0.6” of water. About half the density of the first 12-hour period. You should also consider the fact that the additional snow is likely condensing on the pillow- increasing snow-water equivalent but keeping snow depth the same.
How the storm came in might effect where you choose to go ride in the backcountry, or maybe you just go where it’s the deepest. The point is, by keeping an eye on SNOTELs around your favorite spots, you can tell a lot about the snowpack. It’s usually pretty easy to tell when the storm arrived and how the snow fell. Once you get familiar with it, SNOTEL is a pretty cool tool for the backcountry, and an awesome distraction if you regularly spend all day in front of the computer.