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Modifying Initial Fuel Moisture (BFB & STFB, NTFB)

For BFB, STFB, and NTFB analyses, Fire Behavior Specialists can modify the default fuel moistures for the fuel models on the landscape. When running fire behavior analyses, default initial dead fuel moisture values are NFDRS-calculated values pulled from the RAWS data for the beginning of the fuel moisture conditioning period. Default live fuel moisture values are calculated using the Growing Season Index (GSI). The calculated default values are unique to the weather station that has been selected for the analysis and users can change the values as needed. All fuel moistures can be the same regardless of fuel model, or users can specify fuel moistures for specific fuel models.

The default dead fuel moisture values are the starting fuel moistures used to condition dead fuels for every cell on the landscape extent. Depending on the number of days chosen for fuel conditioning, weather observations are retrieved for that many days previous to the start date and time of the analysis (chosen by the FBS on the General Information page), and are used to condition dead fuel moistures up to the start date and time of the analysis. The conditioned dead fuel moisture values will then be used for calculating fire behavior outputs.

It is important to remember that the live herbaceous fuel moisture (Herb FM) and live woody fuel moisture (Woody FM) values DO NOT change during fuel moisture conditioning, only the dead fuel moisture values are affected by fuel moisture conditioning. Thus, the live herbaceous (Herb FM) and live woody (Woody FM) fuel moistures shown are exactly what will be used to calculate fire behavior. Live fuel moisture defaults generated by GSI are generally closer to reality than those produced by the NFDRS system. These values, however, are simply calculations to be used as a starting point and a surrogate value in the absence of known measured and sampled inputs. Live fuel moisture defaults should be evaluated and adjusted against measured values and observed fire activity as appropriate, especially when using the Scott-Burgan 40 fuel models. 

Generally, if you have selected three to seven days of fuel conditioning, you don't need to change the 1-, 10-, or 100-hour fuel moistures, as they will be conditioned.

To modify initial fuel moisture data:

  1. Navigate to the analysis you want to modify Initial Fuel Moistures for and select it from the Analysis List.
  2. Locate the Initial Fuel Moistures section of the analysis by doing one of the following:
    • Click View Information > scroll down to Initial Fuel Moistures in the right window pane.
    • From within an analysis, click (Model) Information in the left window pane, and then scroll down to the Initial Fuel Moistures in the right window pane.
  3. Review the default initial fuel moisture values for accuracy. These are applied to all fuel models.
  4. If needed, delete the values in each fuel model class and enter desired values.
  5. Optionally, do one of the following:
    • Enter a fuel model number in the Fuel Model Field, and click Add. The fuel model is added to the list and you can enter new fuel moisture values for each fuel model class. Note that you are able to add fuel models even if they do not appear in the Landscape; check that you are entering valid fuel models for the analysis.
    • Click Add Fuel Models from Landscape File. All the fuel models in the landscape are added to the list and you can enter new fuel moisture values for each fuel model class for all the fuel models. You must create the landscape file before you can use the Add Fuel Models from Landscape File button.
  6. Click Save. The fuel moisture data for the analysis is saved.

You can modify fuel moisture values until you run the analysis.

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    Last updated on 6/25/2019 1:33:36 PM.

 

In This Section

Modifying Fuel Moistures for Fire Behavior Analysts

To modify initial fuel moisture data (BFB & STFB, NTFB):

See Also

Modifying Foliar Moisture Content (BFB & STFB, NTFB)

Modifying Fuel Moisture (FSPro)

Reference

Field Descriptions

Glossary Resources

Spatial Data Reference

Landscape Data Source Reference

Relative Risk Reference

Organization Assessment Reference

Fire Behavior Reference

About the WFDSS Decision Editors

To modify initial fuel moisture data (BFB & STFB, NTFB):
  1. Navigate to the analysis you want to modify Initial Fuel Moistures for and select it from the Analysis List.
  2. Locate the Initial Fuel Moistures section of the analysis by doing one of the following:
    • Click View Information > scroll down to Initial Fuel Moistures in the right window pane.
    • From within an analysis, click (Model) Information in the left window pane, and then scroll down to the Initial Fuel Moistures in the right window pane.
  3. Review the default initial fuel moisture values for accuracy. These are applied to all fuel models.
  4. If needed, delete the values in each fuel model class and enter desired values.
  5. Optionally, do one of the following:
    • Enter a fuel model number in the Fuel Model Field, and click Add. The fuel model is added to the list and you can enter new fuel moisture values for each fuel model class. Note that you are able to add fuel models even if they do not appear in the Landscape; check that you are entering valid fuel models for the analysis.
    • Click Add Fuel Models from Landscape File. All the fuel models in the landscape are added to the list and you can enter new fuel moisture values for each fuel model class for all the fuel models. You must create the landscape file before you can use the Add Fuel Models from Landscape File button.
  6. Click Save. The fuel moisture data for the analysis is saved.

You can modify fuel moisture values until you run the analysis.

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Last updated on 1/28/2019 4:10:56 PM.