Dust on Snow

Dark surfaces absorb more light.  Dust settling out of polluted air onto snow, reduces the quantity snowpack as more sunlight (heat) is absorbed.  New Mexico's water cycle depends on the storage of water in the mountains' snowpack to provide irrigation water through the summer months.  Both the timing and the quantity of streamflows are affected by increased dust falling on snow.

Posts - Any technical papers, data, opinions, announcements, etc. that relate to the Dust-on-Snow issue appear just below.

We welcome postings on this or other water-related issues from interested parties.  Please email your posts, preferably in Word format, to the Editorial Board at Info@MRGWaterAdvocates.org

Description of the Issue

The dust-on-snow phenomenon in the mountains of Southern Colorado and Northern New Mexico has a substantial effect on streamflow, including in the Rio Grande, compounding the impact of climate change and thus reducing water supply. This is because settling dust, which darkens the top of the snowpack, makes it less reflective (snow surface albedo), causing melting by making the surface more absorbent of solar radiation. A significant amount of this moisture is lost to evaporation and therefore does not benefit downstream reservoirs.  Loss of albedo can cause snowpack melt up to 50 days earlier than normal, enhancing runoff intensity and decreasing snowmelt yields. This results in peak runoff up to three weeks earlier than normal, with an estimated 5% reduction of annual late spring streamflow.

This problem originates in the Southern Colorado Plateau, encompassing Northwest New Mexico, Northern Arizona and Southeast Utah, which is the dust source area for Southern Colorado and Northern New Mexico. Dust production is a result of disturbance to dryland soil surfaces, caused by many factors, such as recreational vehicles, energy exploration, increased aridity, fire, farm tillage, and predominately by overgrazing. Improved grazing management, which mimics migratory herds of ungulates, can restore soil health and stability, enhance species diversity, and increase water infiltration and retention.

Thus, a major solution to the dust-on-snow issue can be the introduction of regenerative agriculture, including managed grazing and other healthy soil methods in the affected area to stabilize the soil. A project is underway in the Navajo Nation with the intention of restoring soil health to improve local ecologic and economic conditions, while reducing the soil lost through wind erosion, which deposits on the high mountain snowpack.

See the following links for more information.  The second link includes a "crash course" article and a video.

https://www.nmhealthysoil.org/2019/12/01/water-and-soil-health/

http://www.codos.org/