Fire Values Guide
Fire Behaviour Predictions
Real-time predictions of how a fire will behave based on fuel, weather, and terrain.
What is Fire Behaviour Prediction?
Fire behaviour prediction uses the Canadian Forest Fire Behaviour Prediction (FBP) System combined with real-time weather data to forecast how a fire will act. The INFERNIS API provides these predictions for any location in Canada.
Behaviour Parameters
🔥 Fire Type
Surface Fire: Burns along the forest floor consuming litter, grass, and low shrubs.
Intermittent Crown: Flames reach into the tree canopy sporadically.
Active Crown Fire: Fire advances through the tree canopy — the most dangerous type.
📏 Rate of Spread (m/min)
How fast the fire front advances. Surface fires: 1–5 m/min. Crown fires: 50–100+ m/min. Extreme crown runs can exceed 150 m/min (9 km/h).
⚡ Head Fire Intensity (kW/m)
Energy output per meter of fire front. Low: <500 kW/m. Moderate: 500–4,000. High: 4,000–10,000. Extreme: >10,000 kW/m. Fires above 4,000 kW/m cannot be attacked directly.
📐 Flame Length (m)
Vertical height of flames. Surface fires: 0.5–2 m. Crown fires: 10–40+ m. Flame length correlates with suppression difficulty and radiant heat output.
🌳 Crown Fraction Burned (%)
Percentage of the tree canopy consumed by the fire. 0% = pure surface fire. 100% = complete crown fire. Higher values indicate more severe ecological impact.
🌡️ C-Haines Index
Atmospheric stability index (0–13). Values ≥8 indicate unstable atmosphere promoting extreme fire behaviour including pyrocumulonimbus (fire-generated thunderstorms).
Suppression Difficulty Guide
| Intensity (kW/m) | Flame Length | Suppression Capability |
|---|---|---|
| <500 | <1.5 m | ✅ Hand tools effective (rakes, pulaskis, hoses) |
| 500–2,000 | 1.5–2.5 m | 🟡 Heavy equipment needed (bulldozers, pumper trucks) |
| 2,000–4,000 | 2.5–3.5 m | 🟠 Air support required (water bombers, helicopters) |
| 4,000–10,000 | 3.5–10 m | 🔴 Direct attack not possible. Indirect suppression only. |
| >10,000 | >10 m | ⛔ Beyond suppression capability. Wait for weather change. |
How Behaviour Drives Risk
A fire's behaviour — its rate of spread, flame length, and crowning potential — drives every tactical decision crews make on the line.
Behaviour is a function of fuels, weather, and topography. A grass fire behaves very differently from a crown fire in old-growth, even on the same day. Understanding behaviour helps you read smoke columns: a tall, vigorous column indicates active crowning; a low, smoldering plume indicates a creeping surface fire. See Weather for the wind and humidity inputs that drive these changes.