Forest Fire Danger 



497 



AVERAGE COSTS AND DAMAGES PER FIRE 

 FOR EACH CLASS OF DAY 



Class of day 



Item 



345 



Suppression costs $19 $35 $35 $45 $62 



Damages 39 77 95 J 4 2 2 8 



Total 58 112 130 187 270 



organized crews under fire wardens. 

 On bad days, these trained men leave 

 their regular businesses to strengthen 

 the fire-control force; when they are 

 not needed, they return to their usual 

 work. 



By considering fire danger and other 

 factors that affect the speed with 

 which a fire will spread, the forester or 

 fire dispatcher can determine the num- 

 ber of men and amount of equipment 

 it will take to suppress the fire edge 

 faster than it will grow, and thereby 

 bring it under control. It may be 

 calamitous to send too few men, but 

 more than the bare minimum fre- 

 quently cannot be spared especially 

 on bad days when numerous fires may 

 tax the capacity of the control organi- 

 zation to provide crews for all. Each 

 fire on a class 2, 3, 4, or 5 day in the 

 Northeast in its initial stages has been 

 found to require an average of ap- 

 proximately 2, 3, 4, and 5 times more 

 work, respectively, than a fire on a 

 class 1 day. 



The danger measurements are used 

 again in rating the size of the seasonal 

 job-loads on different protection dis- 

 tricts. Administrators can then dis- 

 tribute available funds more equitably 

 among the fire-control districts accord- 

 ing to the needs of each. 



Another practical value of danger 

 measurements was recognized in 1942, 

 when smoke from forest fires blanketed 

 the Atlantic coast and so permitted 

 enemy submarines to roam in com- 

 parative safety. Over the land, the 

 smoke on some days made flying un- 

 safe and halted pilot training. The 

 Army asked help to remove the smoke 

 obstacle. All State and Federal forest 

 fire-control organizations responded. 



802062 49 33 



One of their first steps was to revise a 

 network of approximately 150 fire- 

 danger measuring stations from Vir- 

 ginia and Kentucky to Maine. Forty 

 two stations were moved to critical 

 areas to measure the severity of burn- 

 ing conditions in all parts of the coastal 

 States. Stations were operated by 14 

 States, 6 national forests, 9 units of the 

 National Park Service, the Army, and 

 the Marine Corps. With the ratings 

 obtained from the stations, the State 

 and Federal foresters were better able 

 to recognize dangerous days and in- 

 tensify fire-prevention and control ac- 

 tivities. Consequently, smoke density 

 has been reduced since 1942. 



FIRE-DANGER RATINGS can be com- 

 puted either from measurements or 

 from forecasts of the contributing var- 

 iables. For determining how many men 

 to send to each new fire or for rating 

 seasonal job-loads, ratings based on 

 actual measurements are used. In pre- 

 paring for a bad day, however, the 

 forester must arrange in advance for 

 such fire-prevention activities as radio 

 and newspaper warnings, and mobilize 

 in advance the men and equipment 

 that will be needed. For those pur- 

 poses the severity of danger is rated a 

 day in advance by use of the special 

 weather forecasts now issued by the 

 Weather Bureau, as a regular service. 



As early as 1911, the Forest Service 

 in the West turned to the Weather 

 Bureau for general weather forecasts. 

 But these did not consider specifically 

 enough the weather conditions that 

 affect fires. Accordingly, starting in 

 1913, fire-weather warnings were is- 

 sued when bad fire-weather threat- 

 ened. In 1924, regular fire-weather 

 forecasts, localized by use of weather 

 measurements from the forests them- 

 selves, were started and in 1926 the 

 modern fire-weather service was born. 

 Reports now include a forecast of the 

 weather (degree of cloudiness, fog, 

 smoke), precipitation, wind direction 

 and velocity, temperature, relative hu- 

 midity, visibility, and the extent, direc- 

 tion, and progress of lightning storms. 



