Presentation on theme: "Summer 2009 Western Fire Season Outlook Overview Significant fire potential is expected to be above normal across much of California, Florida, central."— Presentation transcript:
Summer 2009 Western Fire Season Outlook Overview Significant fire potential is expected to be above normal across much of California, Florida, central Texas, eastern New Mexico, and portions of southern Oregon and western Nevada for the following reasons: – La Niña conditions are expected to persist at least through late spring. This will likely lead to cooler and drier than normal conditions across much of the west during late spring and early summer. – Drought conditions exist and are expected to persist or worsen across California, Nevada, Florida, central Texas, and portions of southern Oregon. – Lack of snow pack in the higher elevation areas of California, southern Oregon, and eastern Utah will likely lead to more large fires than normal, depending on lightning activity – Fine fuel loadings from previous year(s) remain a considerable factor for the plains of eastern New Mexico, Texas and eastern Colorado.
Percent of Normal Precipitation – U.S. Note the very dry, persistent signals in CA, SE New Mexico, Texas and Florida.
Percent of Average Precipitation for California Last 3 MonthsLast 3 Years
Percent of Average Precipitation for Western US Last 3 MonthsLast 3 Years
Current and Projected Drought
U.S. Temperature and Precipitation Departures During the Last 30 and 90 Days 30-day (ending 17 Jan 2009) temperature departures (degree C) 90-day (ending 18 Jan 2009) % of average precipitation 90-day (ending 17 Jan 2009) temperature departures (degree C) Last 30 Days Last 90 Days 30-day (ending 18 Jan 2009) % of average precipitation
A majority of ENSO forecasts indicate below-average Sea Surface Temperatures in the central equatorial Pacific through Summer About half of the models suggest La Niña conditions will continue through February-March-April Pacific Niño 3.4 SST Outlook
March through May La Niña Temperature and Precipitation Anomaly Trends and Frequency of Occurrence Temperature Anomaly Temperature Frequency Precipitation Anomaly Precipitation Frequency
Northern California Much of Northern California remains dry this winter and will likely see above normal significant fire potential during the summer. – La Niña conditions will likely limit precipitation and winter snowpack across Northern California, which may lead to more large fires than normal, depending on lightning activity – The Sacramento Valley and Bay Area will likely see above normal significant fire potential due to long-term and persistent drought. – Limited fine fuel growth due to long-term drought could create discontinuous fuels helping to retard fire spread in some areas depending on spring precipitation amounts. – Numerous fire scares from 2008 will provide “fire barriers” that should help mitigate large fire growth in those locations.
Southern California The Central Coast Mountains and Valleys, Sierra Foothills and Sierra Mtn areas will likely see above normal significant fire potential due to long-term and persistent drought. – Lack of snow pack in the higher elevation areas could lead to more large fires than normal, depending on lightning activity – Elsewhere, fire potential is expected to be near normal at least through August. Santa Ana wind events could lead to significant short duration fire activity in the southern coastal and mountain areas during the fall.
Southwest Above normal fire potential in west Texas and eastern New Mexico will spread west into central/southern New Mexico & southeast Arizona later this spring. – The current situation is quite similar to last year, with the southern and eastern portions of the Area remaining quite dry. – Fine fuel loadings from previous year(s) remain a considerable factor for the plains of eastern NM/west TX and the Lincoln NF area in the south-central NM mountains. – Northern AZ and NM, especially the mountains, have benefitted greatly from recent snowfall and are expected to have little chance of large fire activity unless precipitation amounts between now and early summer fall well below normal. – Expect a similar situation to last year this coming spring, with the rangelands of eastern NM/west TX becoming active as temperatures warm and more frequent windy/dry events occur in conjunction with drought and abundant & cured carryover fine fuels. – A significant determining factor will be whether or not the Area gets a few big wet storms like last year. If they do, 2009 will be much like 2008 overall with AZ remaining fairly quiet outside of the southeast portion of the state. If those storms don't materialize, significant fire activity will occur across much of AZ south and west of the Mogollon Rim during the May-June period. – Note: The TFS and state/federal units in eastern NM/west TX are already prepping for severity funds starting about 6 weeks from now.
Great Basin Outlook at this point is for normal fire potential across the Great Basin, except for an area of above normal on the Sierra Front in western Nevada. – Snow pack amounts are near normal except for southeast Utah and eastern Nevada. – Fire activity in the Great Basin has not followed dependable patterns during La Niña years. – Snow melt timing and spring precipitation during March, April, and May are the key indicators of fire activity in the Great Basin.
Rocky Mountain Area Outlook at this point is for normal fire potential across the Rocky Mountain Area this summer. The eastern foothills and adjacent plains of Colorado, extending east into southern Kansas and southwest Nebraska will likely see above normal significant fire potential this spring (pre-green up). – Snow pack amounts are above normal across much of the higher elevation areas in western Colorado and below normal in southwest Wyoming, eastern Colorado and southern Kansas. – The strongest trend during La Niña years is for below normal precipitation across eastern Colorado, Kansas and Nebraska during the spring. Warmer than normal temperatures also occur about 40%-50% of the time. – Fine fuel loadings remain above average in eastern portions of the Area. – Summer fire activity will be dependent on the strength of the Southwest Monsoon and dry lightning activity.
Northwest At this point, normal significant fire potential is expected across most of the Northwest through early summer. – Cool and somewhat wetter than normal La Niña conditions should allow for continued snowpack accumulation and precipitation through early spring in most locations. – Drier than normal precipitation patterns are quite common following La Niña winters during late spring and early summer, especially in southern Oregon and east of the Cascades. – Numerous mid and lower elevation large fires are likely east of the Cascade Crest if precipitation patterns turn dry late this spring. – Southeast Oregon and the Okanogan Valley areas remain relatively dry.
Northern Rockies At this early date, normal to below normal fire activity is expected across the Northern Rockies. – Cool and somewhat wetter than normal La Niña conditions should allow for continued snowpack accumulation and precipitation through early spring in most locations. – Southwestern North Dakota remains relatively dry and could see periods of large fire activity.
Texas and Florida Above normal fire activity is expected across much of Texas, Florida, and portions of Oklahoma. – Very dry conditions along with the presence of abundant fine fuels will cause fire danger to spike in central Texas, especially during windy periods combined with low relative humidity often occurring in conjunction with cold fronts. – Developing drought in Florida is expected to result in above normal initial attack activity and significant fire potential later this spring and possibly into early summer.