Earth Notes
3:21 am
Wed March 25, 2009

Earth Notes - Climate Change III: Dunes on the Move

Flagstaff, AZ – Earth Notes: Climate Change III: Dunes on the Move

As the global climate warms, spring in the desert Southwest is changing. Researchers suggest that the season will get longer, warmer, windier and drier. On the Navajo Nation, that could stir up a rise in dust storms, and put sand dunes on the move.

Margaret Hiza is a geologist with the U.S. Geological Survey in Flagstaff. She's been visiting the Navajo Nation since 2001, marking the locations of sand dunes with rebar and colored flags.

She's finding that a sand dune can migrate three feet in a single storm. In dry and windy conditions, it's not uncommon for a dune to travel 50 feet in a year.

That's unfortunate for people who unknowingly built their homes in the paths of dunes. A few homes in Tuba City have already been buried. Roads must be cleared when windswept sand moves across them.

Sand is rich in minerals, and in wet years dunes can support forage for wildlife and livestock. But in a drought plants don't thrive there.

Hiza says climate change is proving to be a double whammy for dune plants. When spring comes early, plants start growing. Then they're left hanging out to dry, because summer rains arrive too late to support them. The result? Often it's the spread of invasive species like tumbleweed.

Northern Arizona isn't the only place facing an increase in sand dune activity. Hiza is collaborating with researchers who have worked in Mongolia's Gobi Desert, trying to protect villages there from similar dunes on the move.

-Anne Minard