CODOS Update April 22, 2024: Statewide Observations — Colorado Dust-on-Snow Program (original) (raw)

Greetings from Silverton,

The location of dust layers in the snowpack are pretty consistent throughout the Colorado Mountains. We visited our 11 sample sites the end of last week ending on Saturday. Of these sites, where the snowpack is deep (> 4 feet) dust layers D1 and D2 that occurred close together around the first of March are essentially merged together and approximately 1’-2’ under the snow surface depending on the location. This dust layer is the most severe dust layer in the snowpack. The second dust layer comprises of D3 and D4 that occurred close together as well around April 1. This layer is under approximately 5” of recent new snow accumulation towards the Eastern and Northern sites, and at the surface towards the Southern. Where the snowpack is naturally shallow (McClure, Spring Creek, Park Cone, Willow Creek) all of these dust layers are essentially at the surface of the snowpack.

Dust severity is consistent along the Front Range sites (Hoosier, Loveland Pass, Berthoud Pass) including Willow Creek and Rabbit Ears Pass, where the uppermost layer is of moderate severity while the deeper layer is a good bit more severe. Towards the Central Mountains, McClure Pass and the Roaring Fork region is having another bad dust season where the severity is much worse than surrounding regions. In the San Juan Mountains, Wolf Creek Pass is the dustiest location observed of the Southern sites, there are even 1-2 more dust layers observed in this snow profile. Perhaps, besides the Roaring Fork region, overall dust severity is in the “average” category, but don’t believe, combined with the weather, it can’t have drastic affects on snowpack ablation.

With dust at the surface in the Central and Southern Mountains, lack of significant precipitation, basin averaged SNOTEL data is showing a big nosedive in SWE over the last ~11 days (see graphs below), and a corresponding pop in streamflows. And it is going to keep ramping up as the more severe dust layer pops to the surface. Without some meaningful precipitation snowmelt season could be over quickly.

There isn’t much excitement in the forecast for Central/Southern Colorado over the next few days, but the NWS says cooler and unsettled conditions move in Thursday ushering in a series of systems that has potential to bring substantial mountain snow. Hopefully at the very least it will result in a significant albedo reset. After that? Stay tuned.

For specifics about our observations please see pictures and comments below. If you have any questions about your neck of the woods don’t hesitate to call or email.

You can view the snow profile forms here.

Take Care,

Jeff Derry

SWAMP ANGEL (Red Mt Pass): April 17

On April 17 we measured 25.8” SWE at Swamp Angel. Nearby Red Mt SNOTEL reported 21.6”. Dust event #3 and #4 are on the surface of the snowpack and comprises the top 4” of the snowpack. 20” below the surface is the dirtier D1/2 dust layer, very obvious in the photo. With the forecast calling for mostly sunny conditions the surface dust will hasten melt, and once D1/2 reach the surface melt will kick-in in earnest over majority of remaining snow. The snowpack is moist and isothermal.