Avalanche Danger, Snowpack Soar After Massive Storm
Colorado has weathered its first major storm, the snowfall — upwards of 9” over the weekend in LakeCity — combined with gusty winds resulting in significant avalanche danger as of mid-weekthroughout the San Juan Mountains. As of Tuesday portions of the Elk Mountains including the towns ofCrested Butte and Mt. Crested Butte were listed in red as Category 4 with dangerous conditions, whilethe San Juan Mountains, and both southern and northern portions of the San Juan Mountains,including Lake City, are within an area of unstable and drifting snowfall which is considered of“considerable” avalanche danger according to Colorado Avalanche Information Center.For the San Juans, says the information center, a Special Avalanche Advisory remained in effect as ofWednesday with new snow and powerful wind creating dangerous conditions with the likelihood ofhuman-triggered avalanches. Recreationists are advised to limit their activities to slopes less thanabout 30-degrees without steep overhead slopes. “You can easily trigger an avalanche at all elevationsand on all aspects,” says the Avalanche Center“ recent avalanches, shooting cracks, and collapsesare signs of unstable snow and signs to stick to lower-angle terrain.”Apart from snow field fissures and unstable, wind-blown cornices at higher terrain, last weekend’swindfall in terms of snow and water content comes at an opportune time following recent months andweeks with minimal, below average snowfall. Natural Resources Conservation Services’ 11,560’-elevation SnowTel site on Slumgullion Pass above Lake City is now up to 89 percent medianprecipitation as a result of last weekend’s storm and continuing, intermittent snowfall this week.Snow depth at the upper Slumgullion snow gauge site was just 17” as of January 1 and increased to 20”depth on January 10; following last weekend’s snow dump and as of Tuesday, January 16, SlumgullionSnoTel now stands at 29” snow depth with a corresponding 5.8” of weather content. Median snowwater content for this time of year on Slum is 7.4” water, hence we are now at 89 percent of the medianin terms of water which is locked in the snow. The median — as patiently explained by BruceHeath — is the point where there are as many readings above as there are below based on snowdata which has been collected from 1991 to 2020.As a result of this most recent massive storm, Gunnison River Basin, which includes the Lake Fork,is now 94 percent of the 30-year median while adjoining Upper Rio Grande is slightly less, 71percent of long-term median. Percentages for these and other Colorado water basins are highlighted in Natural Resources Conservation Service map whichis illustrated below. In addition to the Slumgullion SnoTel site, other neighboring SnoTel site readings post-storm includeWager Gulch, 11,132’, on the upper Lake Fork which as of Tuesday clocked 23” snow depth with 4.2”water content; by comparison snow depth at the upper Wager Gulch reading site stood at just 13”snow depth with 2.7” water on January 1.On the Upper Rio Grande, the Bear Town snow measuring site, elevation 11,600’, had 45” snowdepth with 8.1” water content on Tuesday this week — more than double just 21” snow depth with 5.0”water on January 1.Cochetopa Pass, 10,061’, measured 78 percent of median precipitation on Tuesday, January 16, with14” snow depth and 2.2” water content; in the northern Gunnison River Basin, Butte SnoTel Site, at10,200’ elevation, has a whopping 47” snow depth with 8.8” water content which is 133 percent of the30-year median; Schofield Pass, 10,653’, stands at 99 percent median precipitation as of Tuesday, 63”snow base with 13.4” water.
