Here is an example, Bogus Basin SNOTEL is reference by site number (978) on its site info page and its station id (16F02S) on its historic monthly table file.
The station id is our official data site identifier as a NRCS station. We use that format also for our entire snow course historical records before SNOTEL came to be. It is based on a grid structure of 1 degree lat and long where first 2 digits represent longitude (16 for 116 degrees west), the middle letter is a lat grid (A = 49-48 degrees North, B=48-47, C=47-46, etc.), the next 2 digits are the sequential order of sites installed in the grid (Bogus basin snow course was the 2nd station installed in that 16F grid, and the last letter is "S" for the SNOTEL site co-located with the historic manual snow course of the same name. So the long term manual snow course is Bogus Basin, station id 16F02. These are the official id's used by any other agencies to get the data.
Station ids can also help you locate a particular site on the .pdf SNOTEL map which is available from the
site info page
The site number is our NRCS internal id only for SNOTEL sites. Site numbers are ordered sequentially, so the lower the number the earlier the site was installed. The site number seems more commonly used with the daily or hourly SNOTEL data, while the 16f02s format (or16f02 snow course) generally associates with the monthly snow water content data.
To add yet another layer of complexity, there is also a 'SHEF' (Standard Hydrologic Exchange Format) identifier, which is used by the NOAA National Weather Service. The SHEF id for Bogus Basin is BOGI1.
SHEF was started by an interagency group as a way for all agencies collecting water and climate type data to get it in a common format. You won't see that in the NRCS system, but might if you use other sources such as the National Weather Service.