I've written about snow data, and some information about snow sites. Here I'd like to write about who to find addtional data about the snow sites and other snow sites operated by the Natural Resources Conservation Service National Water and Climate Center, or NWCC.
First, the NRCS is the agency in the US government with the mandate to operate snow sites. Other agencies can operate similar sites for specific purposes for the agencies, eg. NWS or USCE, or its customers, eg. USGS, but the NRCS is the agency with the broad scope to assess the snow and water resources of the areas in the western US, namely the mountain ranges of the western states.
In the Puget Sound and Cascace Mountains in Washington the NRCS operates an extensive network of sites. These sites are located at or above elevations where snow is usually permanent through the winter season after any early season snowmelts. This is usually about the 2,500-3,000 foot elevation.
This is due to several reasons, but most of which is the dynamic weather in western Washington where you have to operate weather data collection sites with real-time telemetry through the extreme ranges of temperatures. This is difficult between 1,000 and 2,500 feet elevation because of the changes of temperatures and rain or snow where thawing and freezing are difficult to operate field sensoers, data collection instruments and real-time telemetry equipment.
It's easier to collect snow data once the seasonal snow is present and the temperatures are consistently near or below freezing where thawing isn't a significant problem through the winter season. It seems backward but practical experience shows it's true, and why there is a lack of snow data sites below 2,500 feet elevation. These sites are usually observartion sites instead of instrumented sites, usually operated by the NWS or state or local agencies.
The other reason is that you want to know the snowfall and snowpack as high in basin as realistically possible to colllect. This provides the range of snow data from the upper most to the lowest elevation for water resources management of basin. This can only be done by the NRCS. That said, below at the sites in and around Mt. Rainier NP.
The first is the site called, but actually southeast of, Paradise. The second is east of the NP boundary west of Mowich Lake. The third is the site just east of the NP boundary on highway 410 at Cayuse Pass.
These sites will provide you a good picture of the snow in Mt. Rainier NP, where you can data all the data for the site. You can locate them on the map of weather sites, see blue tags.