Where Deserts and Mountains Collide The Implications of Accelerated Snowmelt by Disturbed Desert Dust

1
Where Deserts and Mountains CollideThe
Implications of Accelerated Snowmeltby Disturbed
Desert Dust

• Thomas H. Painter
• Snow Optics Laboratory
• University of Utah

2
Snowmelt and Water

• 75 of freshwater comes from snow in the Western
  US
• Mountain snowpack provides enormous, critical
  reservoir capacity
• Early snowmelt increases growing season length,
  evapotranspiration, and temperatures
• Rate of snowmelt controls water management and
  yield

3
Photo Chris Landry, Center for Snow and
Avalanche Studies
4
Snow Albedo
5
Impact of Dust A Perfect Storm
Dust is well timed Dust is well placed Dust is,
well, darker than snow
April 2009
May 2009
6
Changes in Dust Loading
Post-disturbance 1850 AD Pre-disturbance
From Neff et al (2008), Nature Geosciences
From lake sediments in the Colorado Rockies
7
Present
Photo McKenzie Skiles, Snow Optics Laboratory
8
Future Dust Loading
9
Snowmelt Modeling
albedo 0.72 Before disturbance
albedo 0.43 After disturbance
Senator Beck Basin Study Area, Colorado, 2006
Cleaner (before disturbance) Dirtier (after
disturbance )
10
Informing Water Managers
11
Colorado River Basin May 6, 2009 MODIS-DRFS
Daily sunlight absorbed by dust (W/m2)
12
Water in the Colorado River Basin
STAY TUNED