The formula to calculate the Fire Weather Index (FWI) is:
\[ FWI = 0.434 \cdot \ln(ISI) + 0.537 \cdot \ln(BUI) - 1.233 \]
Where:
Let's say the Initial Spread Index (ISI) is 10, and the Buildup Index (BUI) is 20. Using the formula:
\[ FWI = 0.434 \cdot \ln(10) + 0.537 \cdot \ln(20) - 1.233 \]
We get:
\[ FWI \approx 1.38 \]
So, the Fire Weather Index is approximately 1.38
Definition: The Fire Weather Index (FWI) is a numerical rating of fire intensity based on weather conditions.
Formula: \( \text{FWI} = \text{ISI} \times \text{BUI} \)
Example: \( \text{FWI} = 10 \times 20 \)
Definition: The Fire Danger Index (FDI) is a measure of the potential for fire spread and intensity.
Formula: \( \text{FDI} = \text{FWI} \times \text{Wind Speed} \)
Example: \( \text{FDI} = 200 \times 15 \)
Definition: The rate of fire is the speed at which a fire spreads.
Formula: \( \text{Rate of Fire} = \frac{\text{Distance}}{\text{Time}} \)
Example: \( \text{Rate of Fire} = \frac{500}{2} \)
Definition: The Global Fire Weather Index (GFWI) is a measure of fire potential based on global weather conditions.
Formula: \( \text{GFWI} = \text{FWI} \times \text{Global Factor} \)
Example: \( \text{GFWI} = 150 \times 1.2 \)
