Enter the drought factor, temperature, relative humidity, and wind speed into the calculator to determine the Grassland Fire Danger Index.

Grassland Fire Danger Index Formula

The following formula is used to calculate the Grassland Fire Danger Index (GFDI).

GFDI = 0.1 * D * (33 – (0.037 * T)) * (1 – (0.01 * H)) * (W + 10)Variables:

  • GFDI is the Grassland Fire Danger Index
  • D is the drought factor (0-10)
  • T is the temperature in degrees Celsius (°C)
  • H is the relative humidity (%)
  • W is the wind speed in km/h

To calculate the Grassland Fire Danger Index, multiply the drought factor by 0.1. Subtract the product of 0.037 and the temperature from 33. Multiply the first result by this difference. Subtract the product of 0.01 and the relative humidity from 1 and multiply the previous result by this difference. Finally, add 10 to the wind speed and multiply the previous result by this sum.

What is a Grassland Fire Danger Index?

The Grassland Fire Danger Index (GFDI) is a tool used to predict the risk and severity of grassland fires based on weather conditions. It takes into account factors such as temperature, humidity, wind speed, and the dryness of vegetation to calculate the potential for a fire to start, spread, and become uncontrollable. The index is typically used by fire agencies to manage resources and issue warnings to the public.

How to Calculate Grassland Fire Danger Index?

The following steps outline how to calculate the Grassland Fire Danger Index (GFDI) using the given formula:


  1. First, determine the value of the drought factor (D) on a scale of 0-10.
  2. Next, determine the temperature in degrees Celsius (T).
  3. Next, determine the relative humidity (H) as a percentage.
  4. Next, determine the wind speed in km/h (W).
  5. Using the formula GFDI = 0.1 * D * (33 – (0.037 * T)) * (1 – (0.01 * H)) * (W + 10), substitute the values of D, T, H, and W into the formula.
  6. Finally, calculate the Grassland Fire Danger Index (GFDI) using the substituted values.

Example Problem:

Use the following variables as an example problem to test your knowledge:

drought factor (D) = 7

temperature (T) = 25°C

relative humidity (H) = 50%

wind speed (W) = 20 km/h