Albedo (broad band) at Swamp Angel Study Plot was 0.42 (42% reflectance) at mid-day on May 21; albedo values fell as low as 0.35 during the spring of 2013, with considerably more dust mass in the snowpack.

Differential melt rates illustrated in this photo show a dirty snow surface depressed below its level two days earlier at the base of the the clean snow "roller ball".

Differential melt rates illustrated in this photo show a dirty snow surface depressed below its level two days earlier at the base of the the clean snow "roller ball".

View from Peak 13,510' on the western boundary of Senator Beck Basin

View from Peak 13,510' on the western boundary of Senator Beck Basin

Another example of differential melt rates between clean snow – the clean snow ‘donut’ roller from Storm #24 – and dirty snow.  The Storm #24 snow is still visible on the white, north-facing side of this gully, where the roller originated, whereas all of Storm #24 was ablated from the bottom and south-facing side of the gully.  This white ‘donut’ has survived over a week of sunshine.

En route to the Senator Beck Study Plot.

Differential melt rates illustrated in this photo show a dirty snow surface depressed below its level two days earlier at the base of the the clean snow "roller ball".

Stream in upper Senator Beck Basin

Stream flowing out of Senator Beck Basin from under dirty snow cover.

near Senator Beck Study Plot

Andrew Temple looks out from Peak 13,510' on the western boundary of Senator Beck Basin. The same photo was taken May 2009 for comparison.

Andrew Temple looks out from Peak 13,510' on the western boundary of Senator Beck Basin. The same photo was taken May 2013 for comparison.

Andrew Temple pointing to the difference between dusty snow surface and cleaner snow on the left that is overlying the dust layer.

The view down to Telluride from Peak 13,510' on the western boundary of Senator Beck Basin. The same photo was taken May 2013 for comparison.

The view down to Telluride from Peak 13,510' on the western boundary of Senator Beck Basin. The same photo was taken May 2009 for comparison.

Andrew Temple approaching the Senator Beck Study Plot, at 12,180’.  Dust layer D8 was widespread and is clearly evident on the snow surface to the right of the tower.   The very dirty patches below the distant ridgeline are merged D3-D8 dust.  Much of the dust in the alpine terrain in Senator Beck Basin is still buried underneath Storm #23 and #24 snow but dust layer D8 is accelerating the ablation of that cleaner snow.

Gravimetric sampling of dust-in-snow at Senator Beck Study Plot.

Gravimetric dust-on-snow sampling at Swamp Angel Study Plot. A .5m2 block of snow is isolated and divided into 10cm vertical increments. The 10cm deep layers are collected for dust analysis.

Gravimetric dust-on-snow sampling at Swamp Angel Study Plot. A .5m2 block of snow is isolated and divided into 10cm vertical increments. The 10cm deep layers are collected for dust analysis.

Gravimetric dust-on-snow sampling at Swamp Angel Study Plot. A .5m2 block of snow is isolated and divided into 10cm vertical increments. The 10cm deep layers are collected for dust analysis.

Dust particles on the snow surface with snow crystal card for scale.

Dust-on-Snow sampling at Swamp Angel Study Plot in Senator Beck Basin.

Instrument tower at Senator Beck Study Plot

On south and southeast aspects in Senator Beck Basin, absorption of solar energy in dust layer D8 produced enough melt to initiate extensive “wet-loose” avalanches scouring down to the underlying merged D3-7 dust layer.  

Andrew Temple skis into Swamp Angel Study Plot on a dusty snow surface. Cleaner snow remains on mountains above with dust underneath.

Andrew Temple sawing pit face at Swamp Angel Study Plot.

Andrew Temple pointing to the difference between dusty snow surface and cleaner snow on the left overlying the dust layer.

View from near Peak 13,510' on the western boundary of Senator Beck Basin

View from near Peak 13,510' on the western boundary of Senator Beck Basin

Doctoral student Annie Bryant collects dust-in-snow samples at Senator Beck Basin Study Plot.