Rio Grande: Dust layers were merged at the surface in the Rio Grande during our CODOS tour on April 16. It was of greater severity than Swamp Angel. Judging by the amount of precipitation received over the April 19-21 storm event (Wolf Creek and Upper San Juan SNOTEL showed around 0.7" precipitation, 2" snow depth gain, and ~1" reported SWE, basically no precipitation at Lilly Pond which is now showing snow-all-gone, and 0.2" precip, 3" snow depth gain and 0.5" gain in SWE at Upper Rio Grande which is now showing snow-all-gone) any snow covering the dust was superficial, and did not slow down snow ablation any real degree. With the forecast being sunny until the minor storm system this weekend, we can expect continued snowmelt to continue likely even more so with any possible coverage of dust assuredly now exposed at the surface.
Central Colorado: Generally, more precipitation was reported from the April 19-21 storm as you move north. Observations from other snow scientists driving around Colorado yesterday (April 24) reported that dust was not exposed in the Crested Butte area. But near Park Cone SNOTEL, where dust was on the surface on April 16, station data reported 0.5" precip, 0" snow depth gain, 0" added SWE from the April 19-21 storm, so dust is very likely still exposed in that locale. Monarch Pass is showing a good blanket of pink dust. New snow accumulation of ~10" on Grand Mesa was observed from the April 19-21 storm. Mesa Lakes SNOTEL reported 1.4" of precipitation, 6" of snow depth gain and 0.8" of added SWE from the storm. Dust at Grand Mesa area is likely a few inches under the surface but emerging rapidly due to the warm weather at the CODOS sample site. Once D6/D7 is exposed it will encourage melt down to D3-D5 which was 9" below surface on April 14. Like all locations throughout the state, dust is likely already exposed on certain aspects and lower elevations. As a reminder, D5 (and possible D6 and D7) was at the surface on April 19 at Hoosier, Loveland, Berthoud, and Willow sample locations. Observers reported that dust was still covered at Berthoud Pass yesterday.
Weather Forecast: This weekend a minor storm system will take a glancing blow at the San Juans, but no significant precipitation is expected. With low energy, low moisture and an unfavorable storm track we are anticipating overcast conditions, moderate winds and minor flurries at the most.
Looking forward we are seeing another weak system move into the area early and middle of next week. This system has more favorable southwest flow, but only moderate energy and dry air. At present, this incoming system looks more like a dust event than a winter storm, but being several days out an accurate prediction is difficult. This system will likely deliver some snow to isolated parts of the state, but no one location will break any records. The long-term outlook remains hot and dry, just as it has for the majority of the winter and spring so far.
In the News: On Sunday NPR ran an article that was posted on the front page of their national website, along with that the radio portion has been getting airplay. The article discussed the problem of dust on our Colorado snowpack and highlighted the work of CSAS' Colorado Dust-on-Snow Program. You can read the article here. The radio program Here and Now ran the radio version. Rarely does any news piece mention the fact that we are a small non-profit, let alone mention who supports CSAS. So I would just like to send out a big thank you to our funders. Your long-term stable support allows the Director (me), the only full-time employee, and our two seasonal-part-time employees, to stay focused on collecting and reporting the data, because that is what really matters. Most people are surprised to hear that we are a non-profit, because these folks who understand the problem know that it is of such great importance that we must be under the wing of some sort of state or federal government. Not so. Again, a big thank you to the below entities for making what we do possible (list is not exhaustive):
Colorado Water Conservation Board
Colorado River Water Conservation District
Upper Gunnison River Water Conservancy District
Southwestern Water Conservation District
Rio Grande Water Conservation District
Tri-County Water Conservancy District
Dolores Water Conservancy District
City of Grand Junction
Denver Water (raw water)
Denver Water (climate change program)
Bureau of Reclamation
Rio Grande/Colorado/Gunnison/Southwestern Roundtables
Researchers in Senator Beck Study Basin
And also, our thoughts go out to Steve Fearn who passed away this week. I always enjoyed watching Steve and his colleagues piece apart and work through a problem at the Southwestern Water Conservation District meetings. I was marked by his intelligence and fairness.