36 MONTANA : INDUSTRIAL RESOURCES 



precipitation occurs, ami in the extreme northwestern luirt of the state, 30 to 40 

 days. 



While the annual averaire snowfall, in inches, over most of Montana is the 



same as in North Dakota. South Dakota. Nebraska. Iowa, the northern part of 



Missouri and parts of Illinois. Indiana, and Ohio. — .30 inches — 



Two to Three the snow in ilontana is light and dry. resulting: in a much 



Months of lower averajre winter precipitation than is foimd east of Minne- 



Snow Cover apolis. Sioux City. Dodge City and Amarillo. West of the 



main ransie of the mountains in Montana the snowfall, except in 



the hisrh mountains. avera.£;es from 30 to 65 inches, being lowest in the Bitter Root 



valley. 



Over the greater part of Montana there are only CO to !X) days with snow 

 cover, which is the same period of snow cover to be found in a part or North 

 Dakota. Wisconsin, northern Iowa, and districts in ^Michigan. New York and 

 Pennsylvania. In Montana, west of the main range and. according ro the Atlas of 

 American Agriculture, in far northeastern Montana, in Sheridan. Roosevelt. 

 Daniels and parts of Richland and Valley coimties. there are 90 to 120 days 

 with snow cover, which is the same period of snow cover over most of North 

 Dakota, the southern part of Minnesota, and a goodly portion of Wisconsin. Mich- 

 igan and New York. The only district in Montana with an average of more than 

 120 days of snow cover is in the high mountains near the Yellowstone Park. The 

 average date of the first snowfall in the autumn in Montana occurs earlier than 

 it does in the other states named, except most of North Dakota, and northern 

 Minnesota, and the extreme western part of South Dakota and Nebraska. In 

 most of Montana the average date of the fii'st snowfall is from October 1 to Octo- 

 ber 10. but in the southwestern part of the state the average date of the first 

 snow is prior to October 1. This early snow seldom remains or interferes with 

 farm operations. 



There is less interference with plowing and spring planting operations during 

 the months of March to May. inclusive, from days on which precipitation occurs, to 

 most farmers in Montana, than is the case with the farmer in Indiana. Ohio, 

 Pennsylvania. Kentucky, southern Illinois, and a number of other states. In those 

 states there are 30 to 40 days during these three months on which precipitation 

 occurs : in northeastern ^Montana there are only 10 to 20 days, and over the rest 

 of the state from 20 to 30 days, except for a small district near the Idaho line 

 which is not agricultural in character. The average March temperature in Mon- 

 tana is 30.1 degrees, April 46.4 degrees and May .^1.1 degrees. The average precipi- 

 tation in March is .97 of an inch, in April l.ls inches and in May 2.44 inches. 



While Montana does not get the precipitation that the middle western and 

 eastern states do, there are several factors that help to overcome the deficiency. 

 A chai'cteristic of the annual precipitation that is peculiarly fa- 

 Most Precipita- vorable to agriculture is the large percentage deposited during 

 tion During the growing season. The amount received in the months of 

 Growing Season May to August, inclusive, nearly eiiuals that for the remaining 

 eight months. During this same season, over the eastern 

 two-thirds of the state, more than half of the precipitation occurs at night, when 

 evaporation is less active, the moistux'e penetrates the soil to a greater depth, a crust 

 is less likely to form, and a maximum of benefit is derived. From the point of 

 view of interruption to farm work and therefore of economic production, this 

 point is also of significance. "It is of interest to note." states the Atlas of 

 American Agriculture, "that the region of dominant night rainfall is one in which 

 a large amount of wheat is grown, and al.so that the greatest concentration 

 of night rains comes in the harvest season. The advantages of this nocturnal 

 concentration cannot be over-estimated, as otherwise great difficulty would be 



