Colorado Plateau

Is Desertification in the Southwest Affecting

the Colorado

Snowpack?

Chris Landry CSAS – Silverton

Tom Painter, Andy Barrett NSIDC

Jason Neff CU Geosciences

March 25, 2006 near Shiprock

Desert Dust Emission

Possible sources:

• ‘natural’ processes

• drought

• dryland farming

• recreation

• overgrazing

Dust Deposition in Colorado Mtns.

1999

2004

2003

March 31, 1999

Trajectory Analyses

NOAA Hysplit Model

48 hour back-trajectories

Dugout Ranch Wind Speed

Radiative effects of desert dust deposits in alpine snow TH Painter1, C Landry2, J Neff3, AP Barrett1

1National Snow and Ice Data Center, 2Center for Snow and Avalanche Studies, 3CU-Boulder, Dept of Geological Sciences

CSAS

Collaborative Research funded by the National Science Foundation Atmospheric Sciences,

Geography, and Hydrologic Sciences Grants #ATM-0432327 to NSIDC and ATM-0431955 to the CSAS

Study Site – Senator Beck Basin

Operated by Center for Snow and Avalanche Studies, Silverton, CO

May 21, 2004Photo courtesy JPL (Ian McCubbin)

Swamp Angel Study Plot 11,050’

Senator Beck Study Plot

12,200’

Measurements• Snowpack: depth, SWE (density), stratigraphy,

grain size & type, temperature, wetness, coverage

• Climatology: air temp, RH, wind speed & direction, precipitation, pressure, dust event trajectories

• Radiation: incoming LW, SW; reflected SW; IR ‘skin’ temperature, snow surface albedo

• Sediment & Dust: mineralogy, concentrations

• Hydrological: temperature, EC, streamflow

Albedo Measurement

Snow Albedo

0.78

126 w/m2

0.60

224 w/m2

April 4, 2003 - San Juan Mountains

Snow Pits

May 2004

May 2005

Observed Snowmelt Swamp Angel Study Plot, Red Mountain

Pass, CO

• 15 inches SWE May 20, 2003

• 0 inches SWE May 28, 2003

May 24, 2006

June 4, 2006

May 17, 2005

May 27, 2005

Spectral albedo SWESnowmelt flux

Preliminary Findings …• Dust deposition appears to significantly decrease snow albedo on a regional scale ...

• The ‘doubling’ of absorbed solar radiation appears to increase snowmelt rates and likely results in a higher amplitude and shorter duration snowmelt hydrograph …

Next Steps …

• Formalize findings on albedo effects ...

• Develop modeling of ‘dust-on-snow’ effects on basin-scale snowmelt timing, intensity, and duration …