When do the majority of structures burn down in a wildland fire?

When do the majority of structures burn down in a wildland fire?

• A. Before the fire front arrives
• B. During the ember cast
• C. After the fire front passes
• D. Only during ignition

Answer: (C)

Most structures burn after the fire front passes because embers and lingering heat continue to threaten buildings once the main flame front has moved through. Burning embers, or firebrands, are carried by the wind and can land on roofs, gutters, vents, decks, and dry vegetation around the structure. If these embers ignite fuel such as dry leaves, pine needles, or roofing materials, a fire can start and grow even though the front has already passed. Residual heat inside attics or crawlspaces, along with hidden fuel that’s been heated but not yet consumed, can also ignite later. Ember cast can cause spot fires ahead of the front, but the bulk of structural losses tends to occur during the post-front period when embers continue to ignite fuels around and within the structure. Ignitions only during ignition or before the front is intense enough to account for the majority of losses is not supported by typical wildfire behavior patterns.

Most structures burn after the fire front passes because embers and lingering heat continue to threaten buildings once the main flame front has moved through. Burning embers, or firebrands, are carried by the wind and can land on roofs, gutters, vents, decks, and dry vegetation around the structure. If these embers ignite fuel such as dry leaves, pine needles, or roofing materials, a fire can start and grow even though the front has already passed. Residual heat inside attics or crawlspaces, along with hidden fuel that’s been heated but not yet consumed, can also ignite later. Ember cast can cause spot fires ahead of the front, but the bulk of structural losses tends to occur during the post-front period when embers continue to ignite fuels around and within the structure. Ignitions only during ignition or before the front is intense enough to account for the majority of losses is not supported by typical wildfire behavior patterns.