Crown Fraction Burned (CFB) is a fraction between 0 and 1 indicating the severity of a passive crown fire (Van Wagner 1989, 1993). A value of 0.0 indicates a surface fire while 1.0 represents an active crown fire. Intermediate values represent a scaled value of passive crown fire severity.
These intermediate values can be categorized as follows,
|
Crown Fraction Burned (CFB) |
FireSeverity |
|
0 to 0.001 |
Surface |
|
0.001 to 0.25 |
Low-grade passive |
|
0.25 to 0.6 |
Mid-grade passive |
|
0.6 to 0.9 |
High-grade passive |
|
> 0.9 |
Active |
CFB is different for the two crown fire calculation methods available in FlamMap. A more complete discussion of those differences can be found in Scott (2006).