"The image shows the change in snow water equivalent (SWE) over the last 24 hours at all available Natural Resources Conservation Service Snow Telemetry (SNOTEL) sites in Colorado. Grey shading denotes areas that are over 2850m in elevation. The image is updated every three hours. As a very rough rule of thumb you could multiply the SWE by 10 to obtain a new snow depth. SNOTELs are installed for the primary purpose of monitoring water resources (hence the major rivers are shown) but it also makes an excellent visualization of where the best skiing is likely to be."