Southern San Juan
SnowpackChris Bilbrey · Feb 24, 2019 · Southern San Juan
Weather
High clouds provided an overcast morning giving way to sunny skies in the afternoon. From 2/18 to 2/23, SNOTEL sites in La Plata Mountains recorded 79 inches of snow and 5.2 inches SWE. Since peak accumulation period, 22 inches of settlement observed at same SNOTEL sites.
Snowpack
New snow is deep and travel in the La Plata's is very tough right now. It was a team effort to climb 2500 feet today. Southerly and easterly-facing slopes formed a thin (2 cm), breakable sun crust from warm and sunny weather on 2/23. It made for some challenging skiing. Northerly-facing slopes are soft and deep. Near-surface facets formed during dry weather at the end of January were a meter deep under February storm snow and non-reactive in our stability test. Observed no signs of instability in recent storm snow outside of loose dry sluffing on SW slopes from afternoon sun and heating. Natural activity during this past storm was not as widespread and abundant as mid-January cycle, but slopes that did slide produced large to very-large avalanches. Numerous slide paths above canyon bottom had fresh debris in runout zones. A number of slopes that slid in January slid again during this past week, but did not have the wide propagation as observed before. The problem lies in that a number of slopes that did not slide sit right next to slopes that produced large avalanches. Why did these slopes not slide? Are they only waiting for a trigger? Slope specific evaluation and time will help shed light on the future of instability in this range. Places with a deep overall snowpack also have a strong snowpack, but deep new snow totals still kept us from getting to greedy with our terrain selection today.