Fire Season Outlook 2012 Gina McGuire -­‐ Meteorologist Jess Costello -­‐ Intelligence Randy Dzialo -­‐ Intelligence Nevada Wildfire Facts —  Largest number of fires and largest fires happen in grass/sagebrush. —  Largest number of fires and largest fires are caused by lightning. —  Timing of fire season in any particular year depends largely on curing schedule of fuels (vegetation). —  Some of the biggest fire years tend to happen after two consecutive wet winters that have encouraged widespread growth of vegetation. —  Size of fire / speed of fire spread depends on fuel moisture, wind, fuel loading and continuity of fuels. Through early July 2012 —  Since January, WGB has had 255 reported fires for 86,488 acres as of July 3rd. —  The 5 year average is 163 fires for 5,694 acres through July 3rd. —  An early sign… —  3,177 acre fire in January along the Sierra Front (Washoe Drive Fire) which destroyed 33 homes. To that point, the largest fire WGB had ever seen in January was 32 acres. Seasonal Forecast Techniques —  Best indicators of seasonal probabilities: 1. Fuel conditions. 2. Trends over last 30 years. 3. Analog years. % of Average PrecipitaBon through early July Snowpack in January of 2011 (percent of normal) Snowpack in January of 2012 (percent of normal) Snowpack in late April of 2012 (percent of normal) After two consecutive wet winters, January 2011 shows no trace of drought. After a very dry fall/winter in 2012, drought signatures are seen across the Western Great Basin. NOAA’s Climate Prediction Center forecasts that drought conditions in NV will persist or intensify (brown area) into summer 2012. Nevada has a Bi-­‐Modal Fire Distribution Year to Year: 1. Under 100,000 acres – 10 out of the last 19 years 2. Over 500,000 acres – 7 out of the last 19 years YEAR
FIRES
ACRES
YEAR
FIRES
ACRES
1993
561
52,933
2002
722
84,657
1994
858
198,492
2003
770
16,888
1995
573
88,616
2004
949
42,439
1996
1501
604,727
2005
770
1,031,790
1997
655
43,191
2006
1232
1,341,505
1998
613
80,778
2007
806
886,610
1999
1074
1,612,902
2008
354
65,347
2000
1098
653,676
2009
687
33,365
2001
1128
559,822
2010
485
23,867
2011
815
424,168
Nevada has a cyclical pattern of yearly acres burned:
YEAR FIRES ACRES 1980 621 63,833 1981 666 77,850 1982 442 13,273 1983 474 74,643 1984 744 285,518 1985 974 895,505 1986 845 109,781 1987 870 110,072 1988 906 103,865 1989 590 40,639 1990 889 39,361 1991 843 35,145 1992 976 101,783 1 1993 576 53,001 1 1994 885 199,800 1995 610 91,396 1996 1,318 777,116 1997 703 44,825 1998 740 87,563 1999 1,082 1,616,806 2000 1,098 653,676 2001 1,128 559,822 2002 728 84,760 2003 776 16,890 2004 949 40,486 2005 787 1,032,114 2006 1,274 1,348,871 2007 877 890,152 2008 452 71,930 2009 676 33,348 2010 485 23,867 MEDIAN 87,563 4 1,800,000 1,600,000 5 1,400,000 3 1,200,000 1,000,000 Series1 3 2 3 800,000 600,000 3 400,000 3 200,000 3 0 1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 ENSO (El Nino/La Nina) A WGB study shows that El Nino/La Nina conditions may have a significant influence on Nevada fire seasons. 2011-­‐2012 was a La Nina winter. We just transitioned to neutral with a possible development of El Nino this summer. If/when El Nino develops could have significant effects on the fire season. —  Big Fire Years ( > 500,000 acres burned) – 8 of the last 30 years —  75% of these years were preceded by La Nina winters (6 years) —  The one year the went from La Nina to El Nino (2006) transitioned late in the summer How will transitioning to El Nino affect temperatures and precipitation in the fire season?? May -­‐ July Neutral El Nino June -­‐ August Neutral El Nino Analog Years —  Comparing winter precipitation, state of the ENSO, mountain snowpack, drought status and long-­‐range trends: —  2001 – 559,822 acres burned —  For preceding conditions à 2007 – 890,152 acres burned —  Best fit: ? —  AVERAGE OF ACRES BURNED 2001/2007: approx. 725,000 Comparison of Snowpack 2012 and 2007 Drought CondiBons 2012 / 2007 Drought Monitor June 26, 2012 Drought Monitor June 26, 2007 Soil Moisture 2012 / 2007 Outlook -­‐ July August – October Outlook Conclusion
Fuel conditions and ERCs in June were more representative of the peak of summer fire season, and even above what we would normally see in late July and August, similar to 2007, a big fire year for WGB. Lots of available dead carryover fuels (due to previous wet winters) combined with with record low fuel moistures creates an environment that supports large fires. Continuation of these conditions will likely result in a very active 2012 fire season. Western Great Basin is expected to have an ABOVE NORMAL fire year, especially over the northern half of Nevada, and into eastern Nevada.