El Nino May Boost Fire Danger Weather Pattern Will Mean Less Snowpack In Mountains
Eastern Washington may experience an increased risk of wildfire next summer, thanks to this winter’s El Nino weather pattern, a forestry professor says.
During El Nino years, the Pacific Northwest generally has drier weather with a smaller snowpack in the mountains, and those conditions can boost forest fire danger later on, University of Washington professor David Peterson said.
El Nino is a weather-disrupting condition in the Pacific Ocean that typically occurs every two to seven years when trade winds weaken, allowing warm water normally situated off Australia to drive eastward to western South America.
Meteorologists say this year’s El Nino continues to be very strong and is expected to continue at least into spring.
“Between now and April, we should be seeing the greatest impacts” in the Northwest and across North America, David Battisti, director of UW’s Joint Institute for the Study of the Atmosphere & Ocean, said at a briefing Monday.
The warmer air temperature, rather than a dramatic decrease in precipitation, causes the smaller snowpack.
Oregon’s snowpack right now is the lowest in the Western United States, at only 41 percent of normal, said Jon Lea, hydrologist for the U.S. Natural Resources Conservation Service in Portland. Washington comes in second, with 56 percent of the usual snow.
“We would like to see a bit more snow accumulating at this point in time, but it’s early in the season,” Lea said. “It’s not uncommon to have a slow start.”
Until recently, scientists have not been able to make useful predictions about the effects of El Nino on snowpack, stream flow, forest fires, or fish and wildlife.
The 1982 El Nino was well under way before climatologists recognized something unusual was happening, said Ed Sarachik, a professor of atmospheric sciences.
Since then, researchers have developed a model for understanding the interaction between the atmosphere and the ocean. The model, with data from sea surface temperatures, gives them the ability to issue probability forecasts about climate.
For this El Nino, scientists have access to accurate, daily temperature readings from some 70 buoys spanning one-third of the globe. The buoys are monitored by the National Oceanic and Atmospheric Association’s Pacific Marine Environmental Research Lab in Seattle.
Using data from the buoys, scientists have been able to predict the effects of El Nino six to nine months in advance, Sarachik said.
“We knew this was coming,” he said. “We had some idea of what the climate was going to be like during winter in various parts of the world.”
The data indicate this El Nino is the largest in 50 years and likely the largest this century, said Mike McPhaden, who oversees the buoy operation for the NOAA.
“By several measures, it is unprecedented,” McPhaden said.
xxxx Weather watch El Nino effects in North America range from wetter-than-usual conditions along the Southern California coast to warmer-than-usual winters farther north.