Northern San Juan
AvalancheJim Donovan · Apr 27, 2014 · Northern San Juan
Weather
Poor visibility in the morning. The storm started to break up around 12:00pm but there were still intermittent periods of heavy snow and continued to snow throughout the day. Temperature in the high 20's. Winds were gusty with an average of 10 mph. Winds were N-NW.
Snowpack
Cool temps Saturday evening created a solid freeze for the old snow surface. The old surface was pencil hard. Main avalanche problems for today were wind slab, storm slab and loose dry avalanches. We were concerned with how the new storm snow was bonding with the old surface. Height of new storm snow was 43 cm (17 inches) BTL and was pretty consistent. TL and ATL the snow depth was more varied due to drifting. Height of snow in drifted areas was up to 110 cm in the alpine. Hand shears revealed the storm snow had little cohesion. The storm snow was fist hard. We found some small pockets of wind slabs and were able to get to release with ease. In the alpine we found the layering of the storm snow a little more complicated with fist hard at base of the storm snow and a 4F wind slab about 7cm thick then fist hard to the top. A faint dust layer was also apparent midpoint of the storm snow where the snow was 4F. Winds were strong enough to transport snow. Not a big deal today but the wind transport will be something to look out for in the next couple of days.
Avalanche
Observed a loose dry slide size D1 on a south aspect at 11,600 feet. The slide was approximately 100 feet long and 10 feet wide.