Northern California Fire Behavior Forecast

 

Fire Behavior Forecast for September 2008

 

Current Fire Behavior

For most of the season, fires have been primarily fuels driven with profuse spotting up to a mile ahead of the main fire at times.  Reports indicate that fires are completely consuming 1000 hour fuels in the lower elevation areas with live fuels contributing towards fire spread.  During the last week, winds have been a critical component in fire spread.  Re-burn potential is high in islands of unburned or partially burned fuels.  It is important to consider your local conditions and observed fire behavior when evaluating fire behavior potential. 

 

Predicted Fire Behavior

 

 

Energy Release Component (ERC) values are at record highs in the Northern Sierra, Sacramento Valley, and Mid Coast PSA’s.  ERC values for the Northwestern, Eastside, and Bay Area PSA’s are between the 90th and 97th percentile.  These should start to level off or start to decline by the end of the month.   The Northern Sierra PSA continues to set records for ERC values as well as 1000 hour fuel moistures.  Live fuel moistures for all but the North Coast PSA are below 100 percent. Outputs from NFDRS and observed fire behavior all indicate a continued high potential for moderate to extreme fire behavior across the majority of northern California for September. Expect long-range spotting and increased rates of spread.  Don’t let the shorter days and cooler nights lull you into believing fire season is ending.  Extreme fire behavior can occur in most of the Northern California area in the next few weeks.

The following table summarizes NFDRS outputs taken on September 2.  The cells highlighted in red text indicate values exceeding critical values for each PSA. 

9/2/2008

Bay Area

East side

Mid Coast

North Coast

North Sierra

North eastern

North western

Sac Valley

1000 hr Current

10

6

8

16

6

7

9

6

100 hr Current

8

5

7

12

5

7

8

4

ERC Current

70

91

79

42

91

80

71

95

*Data based on FireFamilyPlus runs for Predictive Services Area using September 2, 2008 1400 weather observations and historic data from 1972.

 

 

Keep informed on fire weather conditions and forecasts.  Remember to watch out when wind increases and/or changes direction.

 

8-4-08

MW