must be trained to anticipate such behavior, and 

 more reliable methods for prediction must be 

 developed. 



STONY RIVER FIRE 



Unobstructed horizontal continuity of fuels 

 had much to do with the rapid advance of this 

 fire. Unexpected shift of wind direction and ve- 

 locity could have resulted from mature cumulus 

 clouds, but few were noted; possible passage of 

 a frontal movement could also have contributed 

 to the large final area of 8,000 acres. 



The lightning fire started on June 22, 1959, 

 and by the next afternoon it had spread to an 

 estimated 5,000 acres. 



The country was flat to rolling; surface 

 weather conditions gave no outward indication 

 of bad fire weather. The wind varied from 5 to 

 12 miles per hour and was gusty; but even so, 

 the smoke column rose rapidly and formed a 

 towering cumulus cloud. A change in the gen- 

 eral atmospheric situation may have influenced a 

 shift of wind at 1330 from northerly to southerly,- 

 the wind aloft caused crowning and a spread 

 rate of 18 chains per hour. Towering cumulus 

 clouds that were observed at 1315 could also 

 have caused the wind shift and resultant fast 

 spread. From 1550 until nearly midnight the 

 surface wind blew from the west, but the clouds 

 came from the southwest. In 9 hours' time the 

 wind swung around clockwise about 270°. The 

 greatest spread rate was 33 chains per hour at 

 about 1700. 



No extreme behavior occurred on June 24. 



The fire spread both to the north and the 

 south on June 25. Mature thunderheads devel- 

 oped by 0800 and persisted until noon, when 

 only fair weather cumulus were reported. A 

 trace of precipitation fell during each 2-hour 

 period from 0800 through 1400; this indicated 

 that thunderheads may have been present later 

 into the day than the record showed. Winds 

 were steady to gusty from 4 to 1 miles per hour 

 from the northwest pushing the fire to the south, 

 but at 1600 the wind shifted to a southwesterly 

 direction and caused trouble on the north end of 

 the fire. The smoke column first rose lazily and 

 spread out gradually, but after 0900 the surface 

 wind carried the smoke away before it rose. 

 Locally unstable atmospheric conditions may 



have accounted for most of the high rates of 

 spread; fuel moisture, relative humidity, and 

 burning index were mild all day. After June 25, 

 the fire spread very little. 



Coupled with a variety of weather condi- 

 tions, the fuels — primarily black spruce — were 

 capable of carrying the flame front with ease. 

 The relatively flat rolling country with few ob- 

 structions also permitted the fire to travel un- 

 hindered. 



From the limited information collected, it is 

 hard to know whether the wind shifts were of 

 local or general nature; however, upper air 

 soundings at Bethel, 175 miles southwest of the 

 fire, indicated a general southwesterly flow of 

 air that was convectively stable at 1400 on June 

 24, in neutral equilibrium at 0200 on June 25; 

 but at 1400 on June 25, layers of air were be- 

 coming convectiveiy unstable. 



The final area was 8,000 acres, about 5,000 

 acres of which burned on June 23. 



HUGGINS ISLAND W-10 FIRE 



Three major runs were observed on this fire. 

 Steep slopes and heavy black spruce fuels were 

 associated with all three. Brisk winds acceler- 

 ated one of the runs, and thunderstorm cells in- 

 fluenced another. The fire was lightning caused 

 on June 19, 1959, attacked on June 24 when it 

 was already 4,500 acres, and abandoned on 

 July 1. It finally burned out at an estimated 

 size of 50,000 acres. 



During June 25, both towering cumulus 

 and altocumulus lenticularis clouds were present; 

 some precipitation fell at 1630. 



At about 2000 the fire, which had been 

 crawling through tundra, reached a black spruce 

 stand on a 75-percent slope and raced through it 

 at about 90 chains per hour,- the average spread 

 for a whole hour was 45 chains. There was no 

 special note of increased or erratic wind; no cu- 

 mulus clouds were present; but the smoke column 

 changed from rising lazily and spreading out, 

 to being carried away by surface winds. This 

 change in the smoke column characteristic may 

 have been an important clue to the sudden rapid 

 spread of the fire, but the changes in slope and 

 fuel type were also pertinent to the cause. There 

 might also have been a topographic influence on 

 local wind flow at that time of day. 



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