Mt. Rainier Snow Pack

As the climb approaches, I've been trying to learn more about snow packs in general and the Mt. Rainier snow pack specifically. 


Here's what I know:

--Year to date snowfall at Paradise is definitely less than last year (530 vs 913 inches), but not terrible (http://www.wrcc.dri.edu/cgi-bin/cliMONtsnf.pl?wa6898)

--Here is an excellent blog written by one of Intern Ranger Carrie Tomlinson (http://mountrainierclimbing.blogspot.com/). It ROCKS!! It has a ton of great info, including why the Muir camera has been out of commission. Her lastest snow pack analysis actually on the mountain - that I could find - is located here (http://mountrainierclimbing.blogspot.com/2012/03/friday-pit-profile.htmll). It comes from a pit dug part way up the face of Panorama point. Good news! It was completely stable with no failures (fractures) in either the Compression Test or the Extended Compression Test (MORE INFO BELOW ON THE CT AND ECT).

Speaking of Panorama point, here is a picture that Carrie took (on a clear day!) showing the route that Cody and I took. 

The route Cody and I took was past the second bunch of trees on the upper left side of the image, where the upslope moves L--> R. 

--All Paradise trails are under snow (http://www.localsnow.org/trailra.htm), although there has been some daytime high temps in the 30s-50s so some of this should be melting... i.e. we shouldn't need snowshoes, thank the fuck Christ (http://www.wcc.nrcs.usda.gov/nwcc/sntl-datarpt.jsp?site=679&days=7&state=WA). This site has the snow pack at Paradise in inches (http://www.skitiger.com/weather/osopvca.htm)

--Specific avalanche updates are no longer occurring but here is an excellent spring avalanche safety synopsis (http://www.nwac.us/forecast/avalanche/current/zone/7/)

--Above 7,000 feet there's been 1-3 feet of snow in the past weekish. Some of this likely melted with higher temps over the weekend with warmer temps and a bit of precipitation. I think this is a good thing in that the higher temps will melt away the looser, more recent snow, leaving the winter snowpack stable underneath. That said, if it starts getting real warm and wet, the water will start seeping down into the deeper layers and create instability in the stable snowpack beneath (http://www.localsnow.org/aval.php?area=crosscou)

--Camp Muir has been cold and there hasn't been much wind in the past coupla days, meaning the snowpack should be pretty stable up there too (http://www.localsnow.org/aval.php?area=muir). 

--Above Muir, all bets are off... 

Here is a link explaining the Compression Test: http://www.fsavalanche.org/Default.aspx?ContentId=22&LinkId=27&ParentLinkId=3

Introduction to the Extended Column Test (ECT):

Purpose is to test the likelihood of both fracture initiation and propagation. In many situations, slabs are initiated by a load (i.e. skier, mountaineer) but do not propagate, the latter of which is necessary to form an avalanche. A compression test is used to evaluate fracture initiation. In other words, the stability of the snow pack. There have been numerous attempts by researchers to test the likelihood of propagation, including testing the shear stability of a column of snow or fracture quality after a compression test. On Rainier, the Intern Ranger has been reporting measurements of propagation with results of the ECT. 

To perform the test (according to the paper I'm reading with other permutations possible), one first cuts out a column of snow roughly 90cm wide by 30 cm downslope (see image on original document: http://www.fsavalanche.org/NAC/techPages/articles/06_ISSW_Simenhois.pdf). One side of the column is loaded like the compression test with 30 taps with increasing force from a shovel, recording the number of taps it takes to both initiate a fracture and subsequently propagate the fracture across the entire cut out column of snow. Also recorded is the depth of the fracture itself. For example, if a fracture initiates at 25 cm deep on the 13th tap and propagates across the column on the 14th tap, the test would be recorded as: ECT 13/14@25. NP indicates that a fracture did not propagate after 30 taps and PP indicates that it only partially propagated, but not across the entire column. Clear as mud? 

The differences between initiation (ECTI) and propagation (ECTP) is important is the key to interpreting the stability of the snow pack. If, for example, a fracture initiates at 15 taps (ECTI =15) and propagates at 28 taps (ECTP = 28) then the column is stable. On the other hand, if ECTI = 13 and ECTI  14, then only a couple additional loading steps (or mountaineering steps) are required to propagate the initial fracture across the entire column. One step fracture, second step slab avalanche. No beuno. 

Of course, the ECT only test one column of snow, not the entire mountain. Plus, these tests - at least in the winter and early spring - are rarely performed at higher altitudes where the risk of avalanche is greater. There are some other limitations, especially when the top layer of snow is lighter, etc. that is beyond the scope of this introduction. 

Hope this helps,

-Patrick