Its Getting Dustier Across The West
June 11, 2013

It’s Getting Dustier Across The West

Michael Harper for — Your Universe Online

Think of the Wild West and it´s likely you´ll conjure up images of tumbleweeds, gold miners settling down at the local saloon for a shot of whiskey, and ultimately, plenty of dust.

Though there are certainly portions of the West that feature plenty of sand and dust storms, other portions are generally free of these conditions.

The University of Colorado Boulder (CU Boulder) has just completed a study claiming that more parts of the West are getting dustier, but they´ve only anecdotal and theoretical evidence to back up these claims.

Researchers in the mostly dust-free areas have never measured for dust, meaning Janice Brahney (lead author of the CU Boulder study) and team had to look for other ways to prove or disprove longtime residents of these areas which claimed they have seen more dust storms in recent years. Using other minerals as a proxy for dust, Brahney´s study claims the amount of dust being cast about the West has increased over the last 17 years and could be due to several factors.

This study is now published in the journal Aeolian Research.

“Dust storms cause a large-scale reorganization of nutrients on the surface of the Earth,” said Brahney. “And we don´t routinely monitor dust in most places, which means we don´t have a good handle on how the material is moving, when it´s moving and where it´s going.”

Since dust doesn´t travel alone, the CU Boulder team measured for other minerals and nutrients which could be carried along in the dust storms. As well, the team measured for minerals in dust storm-free areas.

They settled on calcium deposits which can be cast into the atmosphere before falling back to the earth through rain. This calcium is first sent into the atmosphere as a by-product of burning wood, (such as forest fires or coal-fired plants) ocean spray and, more importantly to this study, soil erosion.

Luckily, the National Atmospheric Deposition Program (NADP) began measuring for calcium deposits in the 70s when scientists first began studying acid rain and its effects on the environment.

Brahney and team studied NADP calcium deposit data from 1994 to 2010 from 175 sites across the West. They found these numbers had increased at the majority of the sites (116 of them) mostly located in the Northwest, the Midwest and the Intermountain West; Colorado, Wyoming and Utah saw the largest increase. Anecdotally, these are also the areas where Brahney and Jason Neff, an associate professor at CU Boulder and co-author of the study say they´ve heard residents talk about an increase in dust storms.

Though Brahney and Neff believe these escalated calcium deposits over the past 17 years could mean an increase in dust, they also claim these numbers could be a conservative estimate as to how much dust is being tossed around. The NADP only collects numbers on dust which has been tossed into the atmosphere and brought down again by rain. The dust which remains below the atmosphere isn´t included in these numbers.

There are many factors at play in this increase of dust storms as well as many implications. This increase could be caused by more frequent windstorms, frequent drought cycles, or even the different ways in which residents are using the land.

This increase in dust storms also has some implications on these western areas. For instance, this kind of erosion could deplete the soil of necessary nutrients responsible for holding moisture in the soil. More dust in the air also leads to poor air quality and low visibility; and when dust ends up in the snowpacks in the Rocky Mountains (as has been witnessed by residents in the area) it absorbs the sun´s energy more easily, causing the snow to melt more quickly than it would have.

Though this study is based on anecdotal and theoretical evidence, the CU Boulder team say they plan to continue watching how and where this dust is spreading to get a better picture of what´s happening in the West.