Fuels. In fire front: 4-percent ground +70-percent brush +80-percent 

 crown. 



Intensity. Maximum energy release rate: 174 X 10^ B.t.u./sec; fire 

 intensity: 8,250 B.t.u./sec.-ft. 



2200. Fire at Ruby Ridge and Ruby Creek; spotting on Caribou Ridge; 

 broken front; brush fire with considerable crowning. 



Weather. Free-atmosphere conditions at 5,000 ft.: Winds 52 m.p.h. 

 SW; relative humidity 31 percent; dry-bulb temperature 65° F. 



Rate of spread. 1.5 m.p.h. 



Fuels. Approximately 30 percent of fuel previously affected by spot 

 fires; fuel available to front: 6-percent ground +80-percent brush 

 +70-percent crown. 



Intensity. Maximum energy release rate: 60 X 10^ B.t.u./sec; fire 

 intensity: 3,800 B.t.u./sec.-ft. 



2300 and on into September 2. Fire moving into Caribou Creek; main front 

 poorly defined; fire cooling down. 



Weather. Free-atmosphere conditions at 5,000 ft.: Winds 49 m.p.h. 

 SW; relative humidity 36 percent; dry-bulb temperature 63° F. With 

 the winds decreasing and the relative humidity increasing, general con- 

 ditions on the fire were improving as shown in table 2. Winds on the 

 fire were about 10 m.p.h. in Ruby, Highland, and Falls Creeks at 0200. 



Rate of spread. 0.5 m.p.h. or less. 



Fuels. In fire front: 6-percent ground +60-percent brush +50-percent 

 crown. 



Intensity. Maximum energy release rate: 7.8 X 10^ B.t.u./sec; fire 

 intensity: 735 B.t.u./sec.-ft. 



Table 2. — Estimates of free-atmosphere conditions from 2200, 

 September 1, 1967, to 0600, September 2, 1967. 



Time 



Wind (SW) 



Relative 

 humidity 



Dry-bulb 

 temperature 





M.p.h. 



Percent 



in 



2200 



52 



31 



65 



2400 



48 



41 



61 



0200 



39 



50 



58 



0400 



31 



62 



54 



0600 



25 



71 



52 



16 



