Understanding Fire Danger Ratings

General Article

Community safety measures such as fire hydrant flow test and fire danger ratings are meant to prepare for disasters and help to prevent them in the first place. The Forest Service uses a color-coded, five-level system to identify the risk and communicate it effectively to the public.

Extreme Fire Danger

Red signs indicate extreme fire danger. This means that all fires have the potential to get seriously out of control. They may be completely unmanageable in areas such as conifer stands and heavy slash. Flames can burn intensely and spread furiously under these conditions.

Very High Fire Danger

The Forest Service communicates very high fire danger by using orange signs. Fires increase quickly and spread rapidly under these conditions and are easier to start no matter the cause. One of the constant hazards associated with very high fire danger is spot fires, which ignite from flying embers or sparks outside the perimeter of the main conflagration.

High Fire Danger

Spot fires remain a hazard of high fire danger, but are more likely to occur only over short distances. It is necessary to fight a small flame immediately when the fire danger is high because it can get out of control very quickly. Yellow signs indicate high fire danger.

Moderate Fire Danger

When the fire danger is moderate, accidental fires are slower to start. They are also slower to spread in wooded areas, although they may spread more quickly in grassland. It is easier to bring a fire under control when fire danger is moderate, indicated with blue signs.

Low Fire Danger

When the fire danger is in the green, spot fires are unlikely. Fuels do not readily ignite unless exposed to an intense source of heat. Flames smolder slowly in wooded areas. They may burn freely in open grassland, but only for a few hours.