Used to indicate the potential for rapid fire growth, due to dry and unstable atmospheric conditions over a fire area. The index is a simple way to measure the atmosphere’s contribution to the fire’s growth potential. A High Haines Index is correlated with large fire growth, where winds do not dominate fire behavior.
| Index | Fire’s Growth Potential |
| 2 | Very Low Potential (moist and unstable lower atmosphere) |
| 3 | Very Low Potential |
| 4 | Low Potential |
| 5 | Moderate Potential |
| 6 | High Potential (dry and unstable lower atmosphere) |