Yes, this still happens to me. I tell somebody that I’m a “meteorologist”, and they ask me if I enjoy the Star Trek series because they presume I study “meteors”. I know, this is a little nuts. But, when it comes to tracking backcountry snowfall around the western U.S., the folks who think I enjoy studying meteors aren’t 100% wrong (perhaps just 99% wrong).
There is a network of backcountry weather stations across the western U.S. called SNOTEL (stands for SNOpack TELemetry). These stations measure air temperature, but their primary job is to measure the amount of water in the snowpack. ‘Water in the snowpack’ you say? ‘Why not just tell me how much snow fell in my favorite backcountry area’? Well, the SNOTEL stations weren’t intended to be useful to skiers but rather for water managers. Since the western U.S. is generally an arid climate and most of the water (50-80%) is stored in mountain snowpack, knowing how much water is up in the hills in the form of snow is extremely important.
This aside, the SNOTEL network still presents valuable data for people who like to slide down snow on two planks. Most of the 750 stations have two sensors that are interesting to skiers: snow height and snow water equivalent.
The snow height sensor determines the depth of snow that’s on the ground. You can use this to indirectly figure out how much snow fell during the last storm. Just take the reading at the beginning of the storm (say, 50 inches) and subtract it from the reading at the end of the storm (say, 60 inches). The difference – 10 inches – is a good estimate of how much snow fell. However, these sensors don’t work perfectly, and often times the data can be very misleading showing less snow than what actually fell.
For another data point, the snow water equivalent sensor measures the weight of the snow to determine how much water is in the snowpack. You can also use this sensor to figure out how much snow is falling during a storm (data is often updated every hour: http://www.wcc.nrcs.usda.gov/snow/), though it’s a bit more complex. For example, at the beginning of the storm the station says that there is 13.0 inches of “snow water equivalent” (SWE), and now midway through the storm there is 13.5 inches. This means that 0.5 inches of fell so far. To convert this to snow, assume about 10 inches of snow to 1 inch of liquid if temperatures are around 25-32 degrees (F), or about 20 inches of snow to 1 inch of liquid if temperatures are around 5-10 degrees (F). So if this is a warm storm, that 0.5 inches of new SWE equals about 5 inches of fresh snow.
All this science is well and good, but you still might be wondering about meteors and how they relate to the SNOTEL sites. It’s pretty cool, actually. These sites were placed back in the 70s, well before satellite communication was widely available. So how do these remote sites transfer their readings to the home office in Portland? They bounce a signal off of disintegrating meteors in the earth’s atmosphere. No, I’m not lying. This is called meteor burst communication, and is both very reliable and essentially free (disintegrating meteors don’t accept credit cards).
Based on these remote weather stations, the snowpack in central and northern parts of the western U.S. is much higher than average this season, through March 16, 2011 (see graphic). And thanks to a creative use of meteors, backcountry skiers can keep track of fresh snowfall in near real time. It’s a good use of taxpayer money – helping water managers and keeping backcountry skiers in the know. Thanks Uncle Sam!
Meteorologist Joel Gratz is the creator of http://www.ColoradoPowderForecast.com and is based in Boulder, CO.