WINSLOW, Ariz. – Instead of spending his time in ceremony one warm night last July, Navajo rancher Robert Diller spent it in his tractor, digging other attendees and their cars out of the sand. He lost count after 10.

The travelers were heading to the ceremonial grounds at Navajo medicine man Ross Nez’ ranch for three days of traditional ceremony to heal their lands of what the Navajo call Sei Nahogishii, “the tumbling sands.” These menacing clouds of sand or dust carried by strong winds often appear as solid walls moving across the land.

“It looked like dust was raining from the clouds – it looked like rain, but it was dust,” said the medicine man’s son, Virgil Nez. “The sand was just grabbing their vehicles.” A bad storm often reduces visibility to nil, and after it passes drivers can find their car partially buried, or sunken.

In the 1930s such dust storms, fueled by poor farming practices, laid waste to farming and grazing lands. Woody Guthrie called it the “Dust Bowl Blues.” With climate change the Sei Nahogishii are again becoming common in northeastern Arizona’s Navajo country, with similar results.

The Navajo have long had a close relationship with the dunes – the land’s resources and its sacred places define their lives. The disruptions wrought by a warming climate are forcing abrupt cultural changes on a people with a long reliance on a once stable ecosystem.

Warming in the Southwest is the most rapid in the nation, and is spurring hot, dry, windy conditions that create dust storms. The Institute for Tribal Environmental Professionals at Northern Arizona University reports that the past five years have seen several of the hottest years on record. The Colorado Plateau region of Utah, Colorado, New Mexico and Arizona had an unprecedented 14 large dust storms in 2009.

The disruption is evident in this dunescape, part of thousands of square miles of dunes that cover the Four Corners region from northeast Arizona into northwest New Mexico. Dunes make up one-third of the 27,000-acre Navajo reservation.

“Dunes in the Southwest are particularly sensitive to climate change,” said U.S. Geographical Survey scientist Margaret Hiza Redsteer, project chief of the Navajo Land Use Planning Project.

Redsteer began studying the dunes several years ago, evaluating drought impacts, and conditions that could worsen or mitigate drought impacts. The study will aid not only in land use planning and in natural resource management, it will provide knowledge of native and invasive plant species, the ecosystem, and vitally, the role of Native peoples.

In normal years, enough rain falls to transform the dunes into ideal grazing for Navajo sheep and cattle. Redsteer predicts that with every 1.8 degrees temperatures climb, about two inches of water will evaporate.

As temperatures rise and evaporation increases, tumbleweeds, invasive plants with a shallow root system move in, crowding out native deep-rooted plants. The animals and people with a reliance on those plants for sustenance can no longer find them.

The wind changes the character of the ecosystem, Redsteer said. Free of vegetation to anchor the soil the once-vegetated dunes become desolate heaps of sand that “reactivates and become mobile.” Strong surface winds can shift entire sand dunes. Runaway dunes bury homes, corrals, feeding stations, pasturelands, and sometimes obliterate entire roads.

The biggest impacts of active sand dunes in this region are on tribal people, whose reservation land is either on, or downwind of, the largest areas of sand dunes. “We’ve gone through droughts before, but never dust storms like this. It’s tearing off roofs, it’s sandblasting exterior walls. Today it blew off the top of my dad’s sheep corral and the barn,” said Nez, casting a quizzical look at the sky. “This never happened in my lifetime. It gets worse every year.”

Nez said his constant worry is the elders, especially when they travel alone. “Everyone carries a shovel in their trunk, but what if their shovel isn’t enough?”

The fine dust settles everywhere, he said. “Sometimes it’s so dense people cannot breathe. A lot of the kids have asthma, and some of the elderlies have to use oxygen.” Dust storms can cause and exacerbate respiratory problems, and heart and lung disease. Sand particles can clog air passages, and cause the person who breathes them to choke.

The Obama administration’s push to develop solar, wind and geothermal renewable energy projects on millions of acres of public land across the west could release more dust. The dust not only carries hazardous particles left over from nuclear testing, it also can carry infectious disease. Physicians for Social Responsibility reports that the incidence of coccidioidomycosis, also known as valley fever, a fungal disease endemic to the southwestern United States, will increase due to increased airborne dust and sandstorms.

Some are quick to blame overgrazing, but grazing is not responsible for kicking up the dust; it’s simply more damaging because surface conditions are now drier due to climate change.

“We usually get a monsoon during the month of July,” said Nez. “A few drops hit the ground this year, that’s all. No rains.” Navajo officials declared a water crisis, and trucked 60,000 gallons of water from Winslow into the Teesto chapter, an hour’s drive over bad roads.

The drought forced many ranchers to part with their herd, Nez said. “The market price for beef was really low, but people were still selling because of the conditions.” With less precipitation, chapter officials are trying to get people to reduce their herds, “but it’s hard. It’s your livelihood.”

Nez has talked with Navajo medicine men “to see what can be done traditional-wise” to stop the Sei Nahogishii. “They offer something valuable like a saddle, take it to the dune and bury it there. We’ve had a few traditional ceremonies for rain, and made offerings to different areas. It’s really hard to talk about these things, some you have to see for it to be explained and understand.”

As evening fell, vehicles on the one-lane road to the Nez ceremonial grounds blocked it in both directions. One hauled a 500-gallon water tank. The dust storm that stranded them settled into a dusty, dirty pink blur across the sky.

Diller’s tractor finally released the last vehicle, a small car buried to its hood, from the sand. It was midnight. “We got them all out!” shouted Nez to his partner. “No damage or injuries.”

For more information about the USGS Navajo Studies, visit http://geomaps.wr.usgs.gov/navajo.