March 15, 2005
ENS

CORVALLIS, Oregon, March 15, 2005 (ENS) - It does not appear there will be any relief this spring or summer from the unusually dry weather that has gripped the Pacific Northwest, according to new projections of drought severity and fire risk that are based on "general circulation" models forecasting global climate.

The analysis, developed by researchers at the U.S. Forest Service and Oregon State University, shows that the northwestern part of the country will face forest and rangeland fires this year that could be unusually severe - the worst of any area in the nation.

Wet weather has covered the Southwest, Central and Atlantic coast regions of the United States, and for these areas 2005 is projected to be a fairly mild fire season.

But the same forecasts for a period from now to August show some pockets of drought severity and associated fire risks in southern Florida, Maine and southeastern Arizona.

There is a fire risk problem of historic proportions developing in a six state region that includes Oregon, Washington, northern California, Idaho, Montana and Wyoming, the scientists said.

"We project that the drought severity the northwestern states are now experiencing will only get worse in coming months, and reach levels that were generally seen during the Dust Bowl of the 1930s," said Ronald Neilson, a bioclimatologist with the U.S. Forest Service and professor of botany at OSU.

Severe drought does not automatically translate into major fires, said Neilson and colleague James Lenihan, a fire and ecosystem modeler.

"It takes ignition sources such as lightning storms to trigger multiple fires, and that doesn't always happen," Lenihan said. "But those events are fairly common and, because of that, fires will often occur if vegetation, moisture and climatic conditions are right, which it appears they will be this year."

The latest consensus forecast for fire risk this spring and summer indicate huge forest and rangeland fire outbreaks in northeastern Oregon and southeastern Washington, and more isolated but severe fire potential in forests near Eugene, Roseburg, Bend and the Portland area in Oregon.

Other severe fires are forecast for parts of southwestern Idaho and parts of Montana.

Unlike short-term weather forecasts, these projections are ultimately based on long-term, global climate models and a "general vegetation model" created by researchers from the Forest Service and OSU, including the work of associate professor of geosciences Chris Daly and the OSU Spatial Climate Analysis Service.

"Last year was a pretty severe drought over quite a bit of the nation, but for various reasons our model didn't really suggest a bad fire year for 2004, and in fact it was a pretty mild year," Lenihan said.

"That was fortunate, because there's some evidence that the low-risk fire years are more difficult to predict than those with higher risk," he said. "When our models show a very high level of fire, as they do now, they are usually pretty accurate."

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