- A concave or cup-shaped char pattern found on the side of fuels exposed to the oncoming fire including small stumps (generally 10 inch diameter and less are more reliable), grass stem ends and terminal ends of brush and tree limbs (generally less than 1/2 inch diameter) that indicate the direction of fire progression at that point. One of the 11 NWCG categories of fire pattern indicators. Source: Guide to Wildland Fire Origin and Cause Determination, PMS 412.
