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Containment on the Pioneer Fire

Many have asked why the percentage of containment on the Pioneer Fire has not increased despite there being limited to no growth of the fire recently.

What does containment mean and how is it measured?

“Containment” indicates how much of the fire perimeter has been surrounded by a control line that the fire will not progress across. Rather than describing how much of the entire fire has been put out, containment refers solely to the perimeter itself and its potential for growth. Containment is normally expressed as a percentage of the entire perimeter. Fire managers will not label a portion of the fireline “contained” until they are confident that the fire will not grow further in that direction.

The Pioneer Fire has not grown in recent days so why is containment not changing?

There are several places in the fire area where very steep, inaccessible terrain has limited the ability for firefighters to construct containment line on the ground. In many of these places, natural features such as rocks and previous fire scars are holding the fire in place. However, firefighters will only change the status of an area to “contained” when there is no heat on the perimeter and no chance for it to grow in that area.

What has been accomplished?

Firefighters have worked to prepare check lines and containment lines, where possible, and in combination with strategically placed water and retardant drops, they have been successful protecting private residences and other infrastructure along the lakeshore and within the Stehekin area. These efforts allowed time for firefighters to put structure protection measures in place throughout the community.

South of the fire crews prepared indirect contingency lines along several key ridges to prevent fire spread towards Manson and completed a shaded fuel break along Cooper Ridge that could be used to slow fire growth and prevent spread towards the Methow Valley.