Updated: 2:36 p.m. Aug. 15

First discovered: 26 days ago, 4:33 p.m. July 20

Initial location: Inyo County, Calif.

Fire type: Wildfire, Type 5

Fire name: Rock

Rock Fire initially started at 4:33 p.m. July 20 in Inyo County, 10 miles north from Independence.

After being active for 26 days, it has burned 12,008 acres of private land. By Saturday afternoon, a crew of 271 firefighters successfully contained the entire fire. It is still undetermined what caused the fire. Fighting the blaze has incurred $15,717,616 in expenses to date, with the projected final cost amounting to $25,000,000.

Brush measuring two feet serves as the primary fuel for this fire.

Wildfire dynamics with two-foot brush as primary fuel

Due to the density and flammability of brush vegetation, brush fires create moderate to high intensity flames. Containment efforts might be challenging, especially in dry and windy conditions, as such wildfire tends to spread rapidly. There’s an increased risk of ember production, which can lead to spot fires as well as brush fuels produce dense smoke.

NIFC Fire Complexity Analysis

This wildfire is considered to be a Type 5 incident, which is the least complex. What it means:

• Resources required are local and typically vary from two to six firefighters.

• The incident is generally contained within within a few hours after resources arrive on scene.

Fire containment

What does 100% containment mean?

Note that full containment doesn’t mean the fire is completely out. In this case, it means that firefighters have managed to get a line completely around the wildfire’s perimeter and it is now stopped from spreading. A fully contained wildfire may continue to burn within the containment perimeter but is not likely to spread.

However, there’s a significant difference between containing and controlling a wildfire. After the fire is fully contained, the next step is to control it. Controlling a fire means ensuring that the fire can’t spread or cross the containment line.

Containment is part of a larger plan for managing a wildfire. It is normally expressed as a percentage and it refers to how much of the fire perimeter has been surrounded/enclosed by a control line that firefighters create. The containment percentage indicates a certain level of control, but it doesn’t always correlate to safety level. Also, it’s important to note that containment doesn’t mean a fire is out.

How is containment measured?

The incident’s central command constantly receives progress reports from firefighters on the ground. As the fireline is constructed, inspected or reinforced, mappers record those details to adjust the containment percentage. The percentage tells the public how much of the fire perimeter is believed to not go beyond the control lines.

Source: National Interagency Fire Center