Dust on snow-capped Colorado mountains behind snowmelt, helping river water supplies: NASA study

dust coat
A coating of dust on snow speeds the pace of snowmelt in the spring. NASA

A recent NASA study has found that dust on the Colorado rocky mountain controls the pace of spring snowmelt regulating water flow in the Colorado River. The research found that faster spring runoff and higher peak flows are regardless of the current air temperatures in the region.

The finding helps in developing a better idea on water management in future by means of advanced knowledge on the response of freshwater resources like snow and ice to the warmer temperatures. Advanced knowledge in this field can also explain the quantity of solar heat absorbed or reflected back to space by Earth. Essentially, this study can help understand better the planet's weather and climate changes.

It has been found that windblown dust or soot covering the snow layer increases the quantity of heat absorbed from the sunlight. Tom Painter of NASA's Jet Propulsion Laboratory in Pasadena, California, found the consequence of dust and snowmelt worldwide in the first-ever study in the field covering spring runoff, the impact of warmer air temperature and the coating of dust on snow.

Changing climate patterns and human land-use has increased the windblown dust in the southwestern part of U.S. Disturbance of the land, lesser rainfall, and removal of protective top soil has resulted in the exposure of bare soil which increases the rate of the issue.

Winter and spring winds carry dusty soil and deposit them on the Colorado rocky mountain. The researcher has found an increase in the annual dust falling by five to seven times more than the mid-1800s.

Tom painter said, "We found that when it's clean, the rise to the peak streamflow is slower, and generally you get a smaller peak. When the snowpeak is really dusty, water just blasts out of the mountains."

Researchers studied data on air temperature and dust in a mountain basin in southwestern Colorado from 2005 to 2014. They also studied stream flow from three major tributary rivers from the mountain which carries the snowmelt water.

It was found that dust determined the spring runoff even during extremely warm air temperature. But the researchers could not find any statistical correlation between air temperature and the pace of the runoff.

Painter said, "As air temperature continues to climb, it's going to have more influence." Temperature affects snow and rainfall. Therefore, it is a prime agent to decide the quantity of snow which has to be melted.

McKenzie Skiles, an assistant professor in the University of Utah Department of Geography and co-author of the study said, "Dust on snow does not impact the mountains that make up the headwaters of Colorado River. Surface darkening has been observed in mountain ranges all over the world, including the Alps and the Himalaya. What we learn about the role of dust deposition for snowmelt timing and intensity here in the western U.S has global implication for improved snowmelt forecasting and management of snow water resources."