Fuels and Fire Behavior Advisory (Predictive Services) Northern California August 6, 2014 Subject: Long term drought conditions along with hot and dry weather have led to critically low live and dead fuel moistures. Weather and fuels conditions are contributing to very active to extreme fire behavior in Northern California. Discussion: The extremely dry and warm conditions of April through July combined with the extreme to exceptional drought conditions have led to critically low live and dead fuel moistures. Numerous large fires experienced extreme fire behavior and rapid growth during the first 4 days of August. Areas receiving precipitation on August 4th and 5th are expected to rebound quickly to extreme conditions. Difference from normal conditions: Live and dead fuel moistures are approximately 6 weeks ahead of normal and typical of early to mid-September. Extreme to exceptional drought, the highest levels on the Drought Monitor system now cover nearly the entire North state. Live fuel moistures never reached typical seasonal maximums and are approaching or have already reached critical levels. All timelag classes of dead fuels are at moisture levels that allow for easy ignition and rapid spread. Concerns to Firefighters: • Expect fires to ignite easier and spread faster due to low live and dead fuel moistures. Recent fires have shown almost complete consumption of large dead fuels. Expect higher probability of ignition and increased spotting due to increased amount of receptive and available surface and aerial fuels. • Current Energy Release Component (ERC) values are reaching maximum seasonal values or setting record highs for almost all Predictive Service Areas (PSA). ERC is a good indicator of seasonal drying trends. Anticipate increased spread rates and active night time burning. • Anticipate higher resistance to control in all fuel types. When critical fire weather conditions exist expect very active to extreme fire behavior. Mitigation Measures: • Firefighters should acknowledge and prepare for fire growth and fire behavior that may exceed anything they have experienced before due to the extreme drought. Normal strategies and tactics may need to be adjusted to account for the drought factor. Suppression actions need to be based on good anchor points, lookouts, communications, escape routes, and safety zones. • Local and incoming fire personnel need to be aware that fire behavior is exceeding normal expectations for this time of the year. Local briefings need to highlight specific fire environment conditions including local weather forecasts, Pocket Cards, ERC’s, live and dead fuel moistures, and special fuel conditions such as mortality, Sudden Oak Death and frost killed brush, etc. • Base all actions on current and expected behavior of the fire. Augment initial attack resources as incident activity dictates. • Review the most current Northern California 7-day Significant Fire Potential along with Daily, Monthly and Seasonal Outlooks at: Predictive Services Outlooks & Fire Potential Area of Concern: The area of concern is all of Northern California. A map showing the areas of concern described in this advisory can be found at: National Fuels & Fire Behavior Advisories
Posted on: Tue, 12 Aug 2014 02:05:15 +0000
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