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Using Gridded Winds (BFB, STFB)

Gridded winds are spatial wind field grids that are useful for examining and calculating fire spread in complex terrain where winds are influenced by topography.  Without gridded winds, each cell on the landscape will have a single windspeed and direction. When using gridded winds, outputs on ridgetops will be stronger than winds in the valley bottom and wind direction vectors will 'bend' around the lee side of terrain features. Proper use of gridded winds in an analysis can produce more realistic fire behavior modeling results.

Gridded winds are an optimal input in (BFB) and Short-Term Fire Behavior (STFB) models and are always run in the Automated versions of these models. Gridded winds are currently not available in Near-Term Fire Behavior (NTFB) but are planned as a future enhancement.

Only two user-defined inputs are required to generate gridded winds: wind speed and wind direction. These inputs are automatically populated (depending on historic or forecast data), but users can override these values if needed. When selecting a wind speed input for gridded winds it is important to note that this value will represent an average across the entire landscape. After running models with gridded winds, users should query the gridded wind outputs to evaluate whether the 'landscape average' wind speed input resulted in reasonable gridded wind outputs at various point locations.The gridded wind model automatically applies a dominant vegetation to the landscape (grass, brush or timber) to account for some level of vegetation drag on the wind field. The model assumes that the selected vegetation type covers the entire landscape. An island of timber in a landscape that is predominantly grass will be treated as grass and the localized effects of the stand of trees will not be represented in the gridded wind outputs.

Gridded winds are generated after an analysis is launched using the WindNinja model. The dominant vegetation type is chosen automatically from the fuels layer and the model utilizes the user-defined wind speed and direction inputs to adjust wind vectors according to the terrain. Wind vectors are created at the (user defined) resolution of the landscape in the model outputs as a color-coded grid with legends that describe the range of modeled wind speeds and directions.

Last updated on 1/28/2019 4:14:26 PM.

In This Section

Analysis for Fire Behavior Specialists

See Also

Viewing Fire Behavior Request Details

Accepting or Refusing an Analysis Request

Granting Analysis Privileges

Downloading a RAWS KMZ File

Analysis Notes

About Analysis Shape Files (STFB, NTFB, FSPro)

Drawing a Landscape Extent

Creating a Landscape Editor Rule

Importing Landscape Editor Rules

Creating the Landscape File

Downloading an LCP File

Editing the Landscape File

Modifying Landscape File Parameters

Viewing the Landscape for an Analysis

Generating a Landscape Critique

Downloading a Landscape Critique

Basic Fire Behavior (BFB)

Running a Basic Fire Behavior (BFB) Analysis

Copying an Existing Basic Fire Behavior Analysis

Analyst_Assisted Short Term Fire Behavior (STFB)

Running a Short-Term Fire Behavior (STFB) Analysis

Copying an Existing Short-Term Fire Behavior Analysis

Near-Term Fire Behavior (NTFB)

Running a Near-Term Fire Behavior Analysis (NTFB)

Setting Up Burn Periods for NTFB

Modifying Wind Information (BFB, STFB)

Modifying Fuel Moistures for Fire Behavior Analysts

About Weather Station Information (BFB & STFB, NTFB, FSPro)

About FWX Weather Files

Downloading FWX Weather Files (FSPro)

Weather Station Availability for Fire Behavior Analysis

Generating Hourly Weather Forecasts

Viewing and Modifying Weather Summary Data (BFB, STFB & NTFB)

Copying an Existing Near-Term Fire Behavior Analysis

Creating an FSPro Analysis

About General FSPro Input Parameters

FSPro Information Menu Option

About Run FSPro Status

Monitoring FSPro Run Status from the Analysis List

About the Date Filter (FSPro)

Copying an Existing FSPro Analysis

About the ERC Stream (FSPro)

About ERC Classes (FSPro)

Setting up FSPro Winds

Editing the FSPro Wind Matrix

Adding or Deleting Rows to the Winds Matrix (FSPro)

Downloading Winds (FSPro)

Recalculating Winds Distribution (FSPro)

Interpreting the Winds Rose (FSPro)

Downloading an Analysis KMZ File

Near Term Fire Behavior Results Downloads

FSPro Fire Behavior Results Downloads

Viewing Analysis Notes

Viewing Analysis Results

Viewing the Analysis Report


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