# Unit 11: Fire Behavior Prediction Systems

Systems Pt. 1 :: Worksheet & Field Guide :: Practice :: Systems Pt. 2 :: Estimating :: Exercises

## Objectives

Upon completion of this unit you will be expected to:

- Describe the differences between point source and line source fire behavior predictions.
- Given weather observations, fuel model, dead and live fuel moisture, slope percent, and midflame windspeed calculate rate of spread, fireline intensity, flame length and probability of ignition using fire behavior tables and formulas.
- Given rate of spread, projection time, midflame windspeed, slope percent, and fuel model calculate area and perimeter of a fire originating from a point source.
- Describe effective windspeed and explain how it is determined for both upslope and downslope fire spread situations.
- Given effective windspeed, rate of spread, and prediction time plot the perimeter of a fire originating from a point source.
- Describe four ways in which actual rate of spread can be measured on a fire perimeter and two ways of estimating flame length.
- Give three ways in which adjustments to predictions of rate of spread and flame length can be made as a result of differences between actual and calculated values.

## Introduction

In this final unit, you will acquire the tools necessary to make basic predictions of fire behavior from the environmental assessments and input data described in earlier units. Please note the instructions to students for this unit are somewhat different from previous units. Here you are required to use the Fire Behavior Field Guide with the workbook. A small calculator is desirable, but not necessary, for the calculations.

The materials in this unit may appear to be highly technical and over-whelming upon first inspection. This should not be the case, since the system presented is relatively simple, and we will take you through it slowly, step by step. The job aids in the field guide are designed to make your assignments as easy as possible. You should have little trouble meeting the unit and course objectives.

This unit will be confined primarily to initial attack fire problems. The predictions system can be applied to larger wildfires; however, the greater variety of fire environmental factors and input values on these fires complicates the process. We'll leave those calculations to the Fire Behavior Officer or the Plans Chief, both of whom have had much more intensive training and experience.