China-Mongolia dust cloud reaches western U.S., Canada

larger   A satellite image taken April 10 shows a mustard-colored dust cloud as it moves eastward from mainland Asia over the Sea of Japan

BOULDER, Colorado (CNN) -- A dust cloud that began in Mongolia and China has spread a haze across much of western North America, according to U.S. weather observers.

The dust cloud, mixed with some industrial pollution from Chinese cities, began two weeks ago along the China-Mongolia border. Prevailing winds have blown it across the Pacific and into the western U.S. and Canada as far inland as Colorado, said Russ Schnell, director of a National Oceanographic and Atmospheric Administration laboratory in Boulder, Colorado.

"It's moving on now and is being diluted by clouds and weather systems. It was very unusual for this dust cloud to have hung together as long as it did," Schnell said in a written statement from the agency.

The plume measured about four miles thick over Colorado and stretches from Canada to Arizona, Schnell said. Canadian observes estimated the cloud stretched at one point for about 1,250 miles (2,000 kilometers).

The cloud started as a sand storm in the Taklimakan Desert in western China and the Gobi desert in eastern Mongolia and was lifted by heavy winds, Rene Servranckx, a meteorologist at the Canadian Meteorological Centre in Montreal, told Reuters.

Observers said the cloud -- which at one time was as large as Japan -- could reach the East Coast, but was likely to dissipate as it moved across the Great Plains.

"It looks like it's going to dipsy-doodle over North America," Jay Anderson, a meteorologist with Environment Canada in Manitoba, told Reuters.

Scientists from NOAA, the National Science Foundation and several universities conducting an already-planned study off South Korea and Japan will monitor any effect the cloud might have on climate, NOAA said.

National Oceanographic and Atmospheric Administration
Canadian Meteorological Centre
Environment Canada

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