Greetings from Silverton,
In Senator Beck Basin (SBB), Senator Beck Study Plot (12,200') held onto snow only a week longer than Swamp Angel (11,100'). Not to say snow is completely gone at higher elevations but it has been going fast. Current snow covered area in the Uncompahgre is around 22% and is 14-28% in the other Southern Colorado, high elevation basins. Of course some of the Central and Northern basins have a bit more snow cover but these basins are also seeing rapid ablation. It has been the worst combination of factors this spring; a shallow snowpack, an average to high-end of average dust-on-snow conditions around the state (which has been solidly exposed since May 2), a complete lack of significant spring storms and in it's stead warm/sunny conditions (at SBB we went 16 days in May without recording any precipitation), all has combined to melt the snow early and fast. With the warm air temperatures evaporative demand is extremely high as well, quickly taking what moisture exists from the soils and plants. The area around "Swamp" Angel is currently very dry with little of the usual wet soils. Typically, it is a very interesting time of the season when snow melts out at SNOTEL stations, leaving the majority of snow at higher elevations above ground-based monitoring networks - except for SBB. And typically when SBSP melts out we see a second surge in the snowmelt hydrograph at Senator Beck stream gauge. But this year according to our observations higher elevations have acquired an amount of snow relative to lower elevations and does not appear we will see much of a second bump.
Warmer weather is expected to continue over the next couple weeks and in the mountains there are chances of afternoon thunderstorms, but that is about it. Please see SWE, streamflow, and SBB plots below.
More from Silverton soon.
Just to make this plot even more busy, I added Snow Covered Area (%) in the Uncompahgre Basin since this is the watershed that Senator Beck is located, and to show the relationship with Uncompahgre River flows. Currently, SCA is around 22% based on the SNODAS Decision Support System. Snow was all gone at SASP by May 16, which is why we see the dive in albedo at that time. Streamflow is well past its peak in Southern Basins and for a number of Central Basins.
Snow under the depth sensor at Senator Beck Study Plot reported 0" as of 5 pm on May 23. Senator Beck stream gauge at 11,000' saw its peak discharge on May 17, whereas most gauges in Southern Colorado, being located lower in their basins and thus integrating all the runoff in the watershed, saw peak the prededing week.
We finally recorded precipitation at SBB over the last four days, but only totaling 8 mm (0.3"). Prior to that we did not see precipitation since May 2.
Ablation rates for a few select SNOTEL stations. Ablation is faster than normal around Colorado. Wolf Creek melted out over 5 weeks early. Rabbit Ears is on track to melt out about 7-10 days early. Red Mt SNOTEL melted about 2 weeks early. And Berthoud is on track see snow all gone about a week earlier than normal.
