Red Flag Warning/National Fire Danger Rating System

September 4th, 2019


Tahoe Fire and Fuels Team

Contact: Lisa Herron, U.S. Forest Service, 530-543-2815

Eric Guevin, Tahoe Douglas Fire Protection District, 775-588-3591

FOR IMMEDIATE RELEASE: September 4, 2019 

Tahoe Fire & Fuels Team Logo

Red Flag Warning/National Fire Danger Rating System 

Fire Prevention is everyone's responsibility! 

LAKE TAHOE, Calif./Nev. – Fire season is now considered a year-round event, particularly in the western United States. In the past, wildfires normally occurred in late summer and early fall when temperatures were high, humidity low and vegetation extremely dry. Local, state and federal fire managers now know that devastating wildfires can occur any time of year, so fire season is now known as a fire year. Sadly, most wildfires continue to be human-caused and are completely preventable. Fire prevention is the key to keeping our communities and forests safe from unwanted wildland fires.

In addition to fire restrictions, which are implemented to help keep our communities and forests safe, the National Weather Service issues Red Flag Warnings and Fire Weather Watches to alert fire departments and the public about critical fire weather and dry conditions that could lead to an increase in wildfire activity. The type of weather conditions that can cause a watch or warning include low relative humidity, strong winds, dry vegetation and the possibility of lightning strikes. Below is an explanation of the difference between a watch and a warning:

  • Fire Weather Watch - issued when fire weather conditions could exist in the next 12-72 hours. A watch is one level below a warning, but keep in mind, fire danger remains high.
  • Red Flag Warning - issued for weather events, which may result in extreme fire behavior that may occur within the next 24 hours. A Red Flag Warning is the highest alert. During these conditions, extreme caution is urged because a simple spark can cause a major wildfire.

In addition to Red Flag Warnings and Fire Weather Watches, the National Fire Danger Rating System (NFDRS) allows fire managers to estimate daily fire danger for a given area. NFDRS uses five different color-coded adjective ratings to help the public understand fire potential. These signs are placed in key locations to alert the public about current fire danger and are most often associated with Smokey Bear. Below is an explanation of the different fire danger levels:

  • Fire Danger Level: Low (Green)
    Vegetation that can feed a wildfire does not ignite easily from small embers, but a more intense heat source, such as lightning, may start fires in duff or dry rotten wood. Fires in open, dry grasslands may burn easily, but most wood fires will spread slowly, creeping or smoldering. Control of fires is generally easy.
  • Fire Danger Level: Moderate (Blue)
    Fires can start from most accidental causes, but the number of fire starts is typically low. If a fire starts in an open, dry grassland, it will burn and spread quickly on windy days. Most wood fires will spread slowly to moderately. Average fire intensity will be moderate except in heavy concentrations of vegetation, which may burn hot. Fires are still not likely to become serious and are often easy to control.
  • Fire Danger Level: High (Yellow)
    Fires can start easily from most causes and small vegetation (such as grasses and needles) will ignite readily. Unattended campfires and brush fires are likely to escape. Fires will spread easily, with some areas of high-intensity burning on slopes or concentrated vegetation. Fires can become serious and difficult to control unless they are put out while small.
  • Fire Danger Level: Very High (Orange)
    Fires will start easily from most causes. The fires will spread rapidly and have a quick increase in intensity, right after ignition. Small fires can quickly become large fires and
    exhibit extreme fire behavior, such as long-distance spotting and fire whirls. These fires can be difficult to control and will often become much larger and longer-lasting fires.
  • Fire Danger Level: Extreme (Red)
    Fires of all types start quickly and burn intensely. All fires are potentially serious and can spread very quickly with intense burning. Small fires become big fires much faster than at the "very high" level. Spot fires are probable, with long-distance spotting likely. These fires are very difficult to fight and may become very dangerous and often last for several days, weeks or months.

It's important that residents and visitors in the Tahoe Basin educate themselves about wildfire prevention, share information with family and friends, and take steps to prevent a wildfire from sparking. One less spark means one less wildfire! For tips on preventing wildfires, visit


About the Tahoe Fire and Fuels Team

The Tahoe Fire and Fuels Team (TFFT) consists of representatives of Tahoe Basin fire agencies, CAL FIRE, Nevada Division of Forestry and related state agencies, University of California and Nevada Cooperative Extensions, the Tahoe Regional Planning Agency, the USDA Forest Service, conservation districts from both states, the California Tahoe Conservancy and the Lahontan Regional Water Quality Control Board. Our Mission is to protect lives, property and the environment within the Lake Tahoe Basin from wildfire by implementing prioritized fuels reduction projects and engaging the public in becoming a Fire Adapted Community.

For more information, visit