Implications of Fire Behavior Forecast Adjective Ratings

**IN THOSE AREAS AS DEFINED ON THE FIRE BEHAVIOR FORECAST MAP WHERE VERY ACTIVE TO EXTREME FIRE BEHAVIOR POTENTIAL EXISTS..... THIS MEANS OVERALL SURFACE FLAME LENGTHS OF 15+ FEET. EXTREME CROWN RUNS ARE POSSIBLE IN HEAVY TIMBER. SPOTTING COULD BE LONG RANGE AND RATE OF SPREAD COULD BE IN THE MILES PER HOUR. (SEE MAP ABOVE)

A BehavePlus 3.02 calculation using fuel model gr4, 1 hr.fuel moisture of 3%, a midflame windspeed of 8 MPH, a live fuel moisture of 30%, and 0% slope calculates a rate of spread of 255.6 ch/hr (that is over 3 mi/hr) with a head fire flame length of 16 ft. Fire size after 1 hour is 1813 acres. All structures within many miles downwind of an established fire in these conditions are immediately threatened.

**IN THOSE AREAS AS DEFINED ON THE FIRE BEHAVIOR FORECAST MAP WHERE ACTIVE TO VERY ACTIVE FIRE BEHAVIOR POTENTIAL EXISTS..... THIS MEANS OVERALL SURFACE FLAME LENGTHS OF 3-15 FEET. MASS TORCHING IN TIMBER IS PROBABLE. SPOTTING COULD BE LONG RANGE AND RATE OF SPREAD COULD BE OVER A MILE PER HOUR. (SEE MAP ABOVE)

A BehavePlus 3.02 calculation using fuel model gr4, 1 hr.fuel moisture of 3%, a midflame windspeed of 4 MPH, a live fuel moisture of 30%, and 0% slope calculates a rate of spread of 96.4 ch/hr (that is over 1 mi/hr) with a head fire flame length of 10.2 ft. Fire size after 1 hour is 419.5 acres. All structures within several miles downwind of an established fire in these conditions are immediately threatened.

**IN THOSE AREAS AS DEFINED ON THE FIRE BEHAVIOR FORECAST MAP WHERE MODERATE TO ACTIVE FIRE BEHAVIOR POTENTIAL EXISTS..... THIS MEANS OVERALL SURFACE FLAME LENGTHS OF 1-7 FEET. TORCHING IN TIMBER IS POSSIBLE. MEDIUM RANGE SPOTTING COULD OCCUR AND RATE OF SPREAD WILL BE UNDER A MILE PER HOUR. (SEE MAP ABOVE)

A BehavePlus 3.02 calculation using fuel model gr4, 1 hr.fuel moisture of 6%, a midflame windspeed of 2 MPH, a live fuel moisture of 30%, and 0% slope calculates a rate of spread of 29.1 ch/hr (that is about 1/3 mi/hr) with a head fire flame length of 5.5 ft. Fire size after 1 hour is 58.1 acres. Direct attack options would be limited to aircraft, dozers, and engines.

**IN THOSE AREAS AS DEFINED ON THE FIRE BEHAVIOR FORECAST MAP WHERE LOW TO MODERATE FIRE BEHAVIOR POTENTIAL EXISTS..... THIS MEANS OVERALL SURFACE FLAME LENGTHS OF 0-3 FEET. ISOLATED TORCHING IN TIMBER IS POSSIBLE. SHORT RANGE SPOTTING COULD OCCUR AND RATE OF SPREAD WILL BE SLOW. (SEE MAP ABOVE)

A BehavePlus 3.02 calculation using fuel model tl8, 1 hr.fuel moisture of 6%, a midflame windspeed of 2 MPH, a live fuel moisture of 30%, and 0% slope calculates a rate of spread of 2.2 ch/hr with a head fire flame length of 2.1 ft. Fire size after 1 hour is .3 acres. Direct attack by handcrews will be safe and effective..