Sierra Front Interagency Dispatch Center

Fire Danger Trend Graphs

Fire Danger Trend graphs display fire danger represented by a fire weather station in relation to it’s past history.  The graphs are generated using this year’s weather data and National Fire Danger Rating Indexes, plotted against historical weather data and National Fire Danger Rating System (NFDRS) parameters.  These graphs are based on selected fuel models and Fire Danger Rating values.  The Sierra Front Fire Managers have chosen the Energy Release Component (ERC) or Burning Index (BI) to best represent local Fire Danger parameters.

v     The graphs are read by comparing the CURRENT fire danger trend (green heavy line) to the HISTORICAL HIGH (red line) and to the HISTORICAL AVERAGE (purple line).

v     The Percentile Value lines (80%/95% or 90%/97%) delineate the historical “Very High” and “Extreme” Fire Danger levels of the selected NFDRS parameter generated by that weather station. 

v     The trends are based on a 3-Day period average, which makes the graph easier to read, but is still representative of fire danger. 

v     The vertical axis of the graph represents the NFDRS parameter value.  The horizontal axis represents the month and day. 

NOTICE:  The National Fire Danger Rating System (NFDRS) is a model that, based on selected parameters, such as fuels, weather, topography, slope, aspect, and elevation, gives a GENERAL picture of the fire danger.  It is not specific to any one fire.  The actual fire may demonstrate behavior that is greater than the model prediction.  Always expect the actual fire to exemplify fire behavior not typical of the model.

Last Updated 11/04/2008
Copyright © 2003 Sierra Front Interagency Dispatch Center