Where Deserts and Mountains Collide

The Implications of Accelerated Snowmelt

by Disturbed Desert Dust Thomas H. PainterSnow Optics LaboratoryUniversity of Utah

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

Photo: Chris Landry, Center for Snow and Avalanche Studies

Reflectivity = 72%

Absorption = 28%

Reflectivity =43%

Absorption = 57%

Snow Albedo

Reflect

ivit

y

Impact of Dust: A Perfect Storm

Dust is well timed

Dust is well placed

Dust is, well, darker than snow

April 2009 May 2009

Changes in Dust Loading

Post-disturbance

~ 1850 AD

Pre-disturbance

From Neff et al (2008), Nature GeosciencesFrom lake sediments in the Colorado Rockies

Present

Photo: McKenzie Skiles, Snow Optics Laboratory

Phoenix 2006

Future Dust Loading

albedo = 0.72

Before disturbance

albedo = 0.43

After disturbance

Snowmelt Modeling

Senator Beck Basin Study Area, Colorado, 2006

Snow

wate

r equiv

ale

nt

(mm

)

Cleaner (before disturbance)Dirtier (after disturbance )

Informing Water Managers

Colorado River Basin

May 6, 2009

MODIS-DRFS

Daily

sun

light a

bso

rbed b

y d

ust

(W/m

2)

Water in the Colorado River Basin

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