2009 North American Fire Season Forecast;
El Niño Forming in Pacific Ocean

Helicopter fighting wildfire

MODIS Active Fire Map — the USFS's Remote Sensing Applications Center generates regional maps for the US fire managers using the active fire locations provided by the MODIS Rapid Response System, and also makes them available through an interactive Arc IMS interface over the conterminous United States, Alaska, and Canada.

MODIS Global Fire Maps — Global 10-day fire maps are generated using the MODIS Rapid Response fire locations to represent the current fire activity across the world.

NOAA North America Fire & Smoke Detection Map — Updated from satellite images daily

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According to the Fire Season Outlook released by the Predictive Services group at the National Interagency Fire Center (NIFC) on May 1st, the areas with the greatest fire potential this summer in the United States are Arizona, New Mexico, northern California and north-central Washington. In Canada, the areas with the greatest fire potential are the northeast region of Manitoba and Saskatchewan, and in Mexico, the north-central area is also expected to be active.

In addition, the Climate Prediction Center (CPC) released an ENSO (El Niño/Southern Oscillation) System Alert on June 4, 2009 stating that conditions are favorable for a transition from ENSO-neutral to El Niño conditions during June — August 2009.

El Niño is an oscillation of the ocean-atmosphere system in the tropical Pacific having important consequences for weather around the globe. Among these consequences are increased rainfall across the southern tier of the US and in Peru (which has caused destructive flooding in the past), and drought in the West Pacific, sometimes associated with devastating brush fires in Australia.

Observations of conditions in the tropical Pacific are important factors in the prediction of El Niño. Sea surface and subsurface temperatures in the Pacific Ocean have increased for the fifth consecutive month, with above-average temperatures extending across the equatorial Pacific Ocean through the end of May. These surface and subsurface oceanic anomalies typically precede the development of El Niño, and most dynamic models now predict the onset of El Niño during the summer of 2009.

As a consequence, the CPC is expecting a robust monsoon season in the U.S. Southwest region, with a drier than normal summer over portions of the Great Basin and Pacific Northwest (see maps below). During the summer of 2009, above normal significant fire potential is expected across portions of Washington, Northern California, New Mexico and Arizona.

ENSO global map showing how a summer-forming El Nino affects weather patterns
These ENSO maps (courtesy NOAA) show how El Niño formations typically affect global weather patterns. The map above shows how a summer-forming El Niño typically affects regional weather, while the map below shows how a winter-forming El Niño typically affects regional weather.
ENSO global map showing how a winter-forming El Nino affects weather patterns

Below normal significant fire potential is expected across portions of Nevada, Colorado, the Southwest, Southeast, and Puerto Rico for the June through September period. The primary factors influencing fire potential this outlook period are:

  • Drought conditions continue to persist or intensify over portions of the West, especially in California, Nevada, and portions of the Northwest.
  • Below normal winter snowpack in north-central Washington and northern California along with warmer and drier than normal mid to late summer conditions will lead to an accelerated drying of fuels.
  • Moderate to severe drought in combination with delayed green-up will likely lead to elevated fire potential across portions of the western Great Lakes through early summer.
  • An unusually wet end to May along with a projected early July robust monsoon will limit fire potential over portions of the Southwest and Colorado.
  • Above normal precipitation across much of the Southeast during May has decreased the potential for large fires.
  • Continued moisture deficits in Nevada are expected to limit fine fuel production and fire spread.

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