Tuesday, November 3, 2009

Snow and snowpack

This is an updated version of the May 2008 post, correcting location information and adding new information.

It's coming to the time folks like to think about visiting Mt. Rainier, but there is still one thing that inhibits or even prohibits the trip. Snow. So it's important to know where you can find the recent snow and snowpack reports, which are done by the NRCS-NWCC in their SNOTEL network, where you can locate sites for Washington.

The SNOTEL sites in and around Mt. Rainier NP can help determine the snow and weather conditions you'll encounter. The best sites for this information are:

Mowich Lake is on the south side of the Mowich Lake road just west of the NP Mowich Lake entrance, and reporting the weather, snow and snowpack in the northwest corner.

Cayuse Pass is almost directly east of Paradise, and at about the same elevation, reporing weather, snow and snowpack at the Cayuse and Chinook Passes. This is a former USGS snow site (1975-2005) recently taken over by the NRCS, which explains the lack of any lengthy historical data. But the NRCS should significantly improve both the reliability and quality of the data from this site.

Paradise is southeast the Paradise area on the Pinnacle Peak Trail, about 0.4 miles in from the trailhead at Reflection Lake.

These will provide a good overview of the snow in the NP, and you can the NPS Website for current trail and camping and weather information and sources.

A note about the data from these sites. Snow and snowpack is measured several ways, so it helps to understand the data. Snow is measured in current depth and new snow and snowpack is translated to snow-water-equivalent (SWE) where the snow is reduced (melted) to the equivalent amount of water or precitpitation used for water resources and watershed models and forecasts. The key for visitors in the spring is to watch the recession of the SWE graph for the snowmelt.

The two pieces of information usually lacking is the snow on the ground elsewhere and the elevation of snow. The former is reported for these sites but not for other areas around the park, except from field (trail and camp) inspections. The latter is important to know when the snow season begins in the fall and when the snowmelt season is underway in the spring. It is the elevation where you will first encounter snow. This rises later in the snowmelt season except in protected areas, such as shade and north slopes.

Additional description and information on snowpack data using the 2009 water years snow data is found here. This post will be updated for the 2010 water year snow data once there is significant seasonal snow, which is usually sometime in mid-late November, and the NRCS begins reporting the stations on the Website.

Photo of Jackson Visitors Center winter 2007 from NPS Website, which is now gone and converted to landscape and additional parking.

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