Posted on | May 27, 2009 | No Comments
This May 24 report from the Los Angeles Times is must read material for anyone looking at the relationship between the desiccation of the western deserts of California, Utah and Arizona by climate change and ground water pumping, the tearing up of fragile dry land by off road vehicles, and the effect of the subsequent dust storms on Rocky Mountain glaciers. These glaciers are crucial to the Western water supply.
From the story:
- Twelve dust storms barreled into the southern Rockies from the deserts of Arizona, Utah and New Mexico so far this year. In contrast, four storms hit the mountains all year long in 2003.
- The storms leave a dark film on snow that melts it faster by hastening its absorption of the sun’s energy. That, coupled with unseasonably warm temperatures, has sped up the runoff here, swelling rivers to near flood stage, threatening to make reservoirs overflow and fueling fears that there will not be enough water left for late-summer crops.
- Dust can speed up snowmelt by as much as 35 days.
- Ever since European settlement of the West, there has been dust. Initially, grazing cattle kicked up the dust. Scientists say it is now more likely to be caused by off-road vehicles, mountain bikers or energy exploration. In a study last year, researchers found that the amount of dust in the Rockies is five times greater than before the late 19th century.
- Even without the dust storms, forecasters predict that global warming will reduce the soil quality in the western United States to dust-bowl levels by 2050. The Southwest’s temperatures are expected to rise by 10 degrees Celsius by 2100.
- Dust and soot are contributing to the disappearance of mountain snows and the disturbance of water supplies all over the world.
- In California, the Sierra Nevada snowpack gets some soot from Asia and from the state’s own smog-emitting centers, but little dust. State officials have begun to study whether that soot could be contributing to a sped-up snowmelt that, if it continues unabated, could someday overwhelm the reservoir system.
- Because winds in the western United States blow from the southwest, dust from the deserts of California, the Great Basin and the Colorado plateau is deposited on the southern Rockies.
- The amounts of wind-blown dust in the West peaked in the 1920s, reaching seven times the historic norm. Scientists think the level of dust dropped after Congress sharply limited cattle grazing in 1934, near the height of the Dust Bowl. Today, levels are five times the historic norm.
- It is only in the last six years that scientists have begun to study dust’s effect on snow and water supplies.
- This year’s storms put the issue of dust front and center. Mountains that usually remain snow-covered until midsummer are already almost bare along the entire western stretch of Colorado.