Ski resorts aren't the only mountainous areas where snow is measured. There are 750 remote backcountry weather stations around the western US that also measure snow (and rain and temperature). These sites are called SNOTEL.
+ SNOTEL sites are remote backcountry weather stations that measure snow
+ The most reliable measurement they make is Snow Water Equivalent (SWE)
+ SWE is measured in liquid inches. It's what you'd get if you melted the snow.
+ Warmer storms mean that 1 inch of SWE is about 6-10 inches of snow.
+ Colder storms mean that 1 inch of SWE is about 15-20 inches of snow.
SWE is measured by weighing the snow. The "snow pillow" on the ground is filled with liquid antifreeze. As snow accumulates on top of the pillow, the antifreeze is squeezed out, automatically measured, and converted into a number that represents SWE.
The Snow Depth Sensor is a downward-pointing laser that measures the height of the snow. However, this measurement is often error-prone because air pockets between and within snowflakes make it hard for the laser to provide a correct measurement.
If you're looking at SNOTEL data and trying to figure out how much it snowed last night (or the few days before), look at the change in SWE in multiply by about 6-10 for heavier, warmer snow and 15-20 for lighter, colder snow.
Bookmark this page to track the snowfall at SNOTEL sites throughout the western US:
Andrew Slater's amazing SNOTEL page
The official SNOTEL site is here.