Fire Weather Forecast
This guide will help you understand the key terms and metrics used in the Fire Weather Forecast reports. These metrics are critical for assessing fire risk and determining appropriate response actions.
High/Low Temperature
The maximum and low temperature forecasted for the day. Higher temperatures can dry out vegetation, increasing the risk of fire ignition and spread.
Low Relative Humidity (RH)
The minimum relative humidity for the day, expressed as a percentage. Lower humidity levels mean drier air, which can increase the likelihood of fire ignition and make fires harder to control.
Wind Speed
The wind blowing speed in miles per hour (mph). Wind can spread fires rapidly by carrying embers and fueling the flames.
Fire Danger Risk (Low, Moderate, High, Very High, Extreme)
This rating provides a general indication of fire danger, based on the Burning Index and other factors like weather and fuel conditions. It categorizes the fire risk into levels: Low, Moderate, High, Very High, and Extreme, with "Extreme" representing the highest concern for potential fire activity.
While this rating offers valuable guidance, it is an estimate and not a guarantee. Fires can occur at any rating level, including "Low" or "Moderate," and sometimes even grow into large, dangerous fires under unexpected conditions. Always exercise caution and remain vigilant, regardless of the rating.
Red Flag Alert
A warning issued when critical fire weather conditions are occurring or expected to occur soon. Alerts are used to prepare for heightened fire danger, often leading to increased readiness and preventive actions. In some situations, the City of Los Angeles enacts additional parking restrictions on Red Flag Days. For more information visit https://ers.lafd.org/redflag/.
Fireline Intensity
A measure of the energy output along the fireline, typically expressed in BTUs per foot per second. Higher fireline intensity indicates more dangerous fire conditions and the potential for more significant fire behavior.
Ignition Component
A measure of how likely it is that a spark or ember will start a fire that needs to be put out. It mainly depends on how dry small fuels are and their temperature. The IC is a percentage from 1 to 100, with higher numbers meaning a higher chance of ignition.
Flame Length
The distance from the base to the tip of the flames. Longer flames can indicate more intense fires that are harder to control.
Burning Index
A number indicating the potential for a fire to occur and spread. It takes into account factors like wind, temperature, and humidity. A higher burning index indicates a higher potential for fires.
1-hour Fuel Moisture
The moisture content of small, fine fuels (e.g., grasses, leaves) that can dry out quickly. Lower fuel moisture means that vegetation is more likely to ignite.
10-hour Fuel Moisture (Observed)
The moisture content of slightly larger fuels that take longer to respond to atmospheric conditions. Like the 1-hour fuel moisture, lower values indicate higher fire risk.
General Note
While we pride ourselves on being experts in wildfire management, wildfire science is complex, and definitions can vary based on context and evolving knowledge. If you notice any discrepancies or inaccuracies in our definitions, we sincerely apologize. We encourage you to reach out to us via hello@lait911.com with your feedback so we can continually improve the accuracy and usefulness of this guide.