Northern San Juan

Snowpack

Susan Hale · Feb 20, 2013 · Northern San Juan

Weather

Snowing S1 to S2 while we were out. Winds were southerly/5-10 where we were. New snow accumulations were at most about 4".

Snowpack

>On the uphill: Southerly aspect had a hefty suncrust with a dusting of new on top. This crust was breakable on lower angle or less exposed terrain. The crust was supportive and slippery on more exposed steeper areas. Around the corner to more ENE aspects W.Lime path: > upper tier snowpack was shallow and weak. Snow depth - 55cm. (This location avalanched during Storm 10, Jan 28th.) New snow along with a portion of the weak upper pack sluffed downhill easily on steeper slopes. Also found a reactive interface in the midpack on facets that had developed within Storm 11 snow (this was below the recent dust layer and above the old bed-surface)CT13 x 3; ECT would not propagate but failed underneath shovel as before (felt the slab was too weak to propagate - at this time). > Lower tier - was quite different with variable windslab depending on slight aspect changes and variable depths, depending on catchments etc. The midpack was stronger and deeper (at least where we dug a quick hole). This portion had sluffed extensively during the recent storm 11 and we suspect that activity strengthened the slab by comparison. The location where we dug was almost 1m deep. Because this mid-pack had more integrity, we were more leery of skiing our traversing below it. The most reactive layer was a facet interface between the new snow and the old surface (RR grains). Sections were flying off the pit wall while digging. This will be a problem layer with the next snow load - most likely a nuisance at first - sluffing easily with little weight. Apart from that particular layer, we felt that the midpack slab would support a decent snowload.