Sasse Ridge Snowpack and Weather

Last site update: Monday, January 05, 2009 (charts updated daily now)

Nuts and bolts: the charts linked in the sidebar show the output of a localized snowpack model that generates twice daily ‘virtual snowpits’ from the summit of Jolly Mtn. to the valley floor. Another copy of the model does the same for Swauk Pass (aka Blewett Pass).

This website has information about the snowpack on terrain accessible on skis via FS Road 4315. It includes the area from the large sno-park at Salmon La Sac to the top of Sasse Ridge directly above, and on to the top of Jolly Mtn. 6443’ elv. This is really just a pet project of mine since I have been averaging maybe 35 to 40 days a winter skiing and ski-camping there; no claims of accuracy whatsoever!

Not so recent changes here.

January 2009 All charts now functional (for the moment!)

December 2007; as an experiment, I’ve adapted the snowpack model to use concatenated NWAC data from Amar’s www.skimountaineer.com website. Thanks Amar! And of course thanks to the Northwest Avalanche Center too.

This is still a work in progress, but here are two links:

recent Snoqualmie Pass charts

If the link above does not work, try this: recent Snoqualmie Pass charts

November 2008

The winter charts for Sasse Ridge and Blewett Pass will be posted AM and PM, seven days a week, but perhaps not at the same times as last year.

At least that’s the plan, depending on how many hits the charts get.

I’ll probably post the NWAC Snoqualmie charts also.

A model of the Sasse Ridge snowpack:

In 2002 I began playing with a quite simple experimental model that estimates the recent additions to the Sasse Ridge snowpack as one ascends from the valley floor. The result is displayed as a bar graph which is much easier to interpret than a long series of numbers. The model and the assumptions on which it is based are discussed here. Since then I’ve added a number of other bits of data to the output; stuff that I find useful.

Data sources:

The Northwest Avalanche Center (NWAC) maintains a large number of excellent telemetry sites in the Cascades, however none are in close proximity to Sasse Ridge.

Fortunately there is a Snotel site at the 4300 foot level on Sasse Ridge that provides hourly data, which can be accessed in many different ways via the web. Snotel sides are owned and maintained by the USDA National Resources Conservation Service and are intended mainly for water resource management. The NRCS website has a vast amount of information about these sites and is worth looking at to understand how the sensors work.

Note that Snotel precip and SWE sensors report only to the tenth of an inch. By comparison, the NWAC sites report to the hundredth of an inch. For newly fallen snow, a tenth of an inch of precip is roughly equivalent to an inch of new. This means that at Snotel sites data scatter is in the order of plus/minus an inch of new snow or more. This is significant for a skier.

For the 02-03 winter, snow depth monitoring was added at the Sasse Snotel site. It seemed to be a useful adjunct, but perhaps because of the location of the site itself and perhaps the nature of the sensor, I think that the general conditions on the ridge were often better reflected by the SWE and precip counters.

Besides data from the Sasse Snotel site, other useful information can be gained from the HADS – DCP site at Cooper Pass, just across the valley to the west. Although the precip gauge has appeared to be erratic for the last few years and not to be trusted, this site has wind speed and direction, as well as temperature. More about this site here. (Access to the Cooper Pass data keeps changing; you may have to web search for it.)

Telemetry sites give an idea about conditions at a particular elevation. However, a skier would like to know how the snowpack changes from the parking lot (2350’ elv.) to the top of the mountain.

Questions or comments, at least friendly ones, welcome at the address at the bottom of the page.

Larry