The Local Fire Risk (CBI) feature in the Dryad Site Management App uses the Chandler Burning Index (CBI) to estimate the likelihood and potential severity of wildfire ignition at your site.
It provides an easy-to-read indicator of real-time and historical fire danger insights, helping you take preventive actions when environmental conditions become critical.
What Is the Chandler Burning Index (CBI)?
The Chandler Burning Index is a numerical measure of fire danger based on temperature and relative humidity.
Higher CBI values mean higher fire risk, as warm and dry air creates conditions more favorable for ignition and rapid fire spread.
How CBI Is Calculated
Dryad automatically calculates the CBI using local weather data collected from sensors or site-level weather feeds.
The formula used is:
CBI = (((110 - 1.373 * RH) - 0.54 * (10.20 - T)) * (124 * 10^(-0.0142 * RH))) / 60Where:
- RH = Relative Humidity (%)
- T = Temperature (°C)
The calculation updates continuously as temperature and humidity change, providing near real-time fire risk information.
Fire Danger Levels
| CBI Range | Fire Danger Level | Description |
|---|---|---|
| < 50 | Low | Fires are unlikely to spread rapidly. Spotting is rare. |
| 50–75 | Moderate | Fires can start from most causes and may spread briskly in grasslands. |
| 75–90 | High | Fires start easily and spread quickly, especially in dry conditions. |
| 90–97.5 | Very High | Fires ignite and spread rapidly; spotting is common. |
| > 97.5 | Extreme | Fires start instantly, spread uncontrollably, and are highly dangerous. |
Where to Find Local Fire Risk (CBI)
You can access fire risk information by opening your deployed site in the Site Management within the Dryad Site Management App.
CBI is available at three levels:
1. Site Fire Risk
At the top of your Site Overview page, you will see the Site Fire Risk (CBI) indicator.
This displays:
- The current aggregated CBI value
- The corresponding fire danger level
This represents the overall fire risk of the entire site, calculated from all available sensor readings.
It provides a quick, easy-to-read snapshot of current conditions.
Clicking the Site Fire Risk indicator opens the Site Fire Risk History panel.
Here you can:
- View historical CBI trends
- Select a custom date range
- Analyze how fire risk has evolved over time
This view shows the aggregated fire risk for the whole site, based on all sensor data.
2. Fire Risk (CBI) Map Layer
You can enable the Fire Risk (CBI) layer on the map view.
This layer:
- Visually represents the overall site fire risk
- Uses color-coded categories (Low to Extreme)
- Provides geographic context of site-wide conditions
This helps you quickly assess the fire situation across the monitored area.
3. CBI Per Sensor (Sensor-Level Detail)
In addition to site-wide monitoring, you can view CBI values for individual sensors.
Within each sensor’s graph view, you can:
- See the calculated CBI for that specific sensor
- Compare fire risk conditions across different parts of the site
This enables more granular fire risk assessment, particularly valuable for large or geographically diverse deployments.
How It Helps
The feature supports wildfire prevention and readiness by enabling you to:
- Monitor real-time fire danger
- Track historical fire risk trends
- Understand site-wide and localized risk patterns
- Plan preventive measures during high-risk periods
- Coordinate response when fire danger levels rise
Important Notes
CBI focuses on temperature and humidity; it does not account for wind, fuel moisture, or fuel load.
- The CBI value does not automatically trigger alerts, but higher values may indicate increased likelihood of fire alert notifications.
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