12 



with any degree of accuracy the number of acres which can be irri- 

 gated from these sources. From a more or less intimate knowledge 

 of the water resources of the State, the writer would place the limit 

 at 6,000,000 acres as being the largest amount of land which can be 

 irrigated in Montana from all sources, including stream flow, storage 

 reservoirs, and wells. 



It may be stated in a general way that for every acre that can be 

 irrigated there will be nearly 2 acres that may be cultivated dry and 

 10 acres that will afford pasture for stock. How to make the l)est 

 possible use of 6,000,000 acres of irrigable lands, of 10,000,000 acres 

 of arable bench lands, and of 50,000,000 acres of grazing lands is the 

 most vital and far-reaching question that is likely to arise in Montana 

 for the next quarter of a century. It has always seemed to the writer 

 that the ideal farm in this mountain State would consist of 40 acres of 

 irrigated land wdth a good water right, about 40 to 80 acres of arable 

 bench land, and about 640 acres of fenced grazing land on a near-by 

 mountain slope. 



CLIMATE. 



The climate of Montana is arid and is typical of nnich of the Rocky 

 Mountain region, but nearly TO per cent of the average precipitation 

 of 14.5 inches occurs during the crop-growing season. Few records 

 have been taken to show the heavy precipitation on the mountain 

 slopes. The officers of Fort Yellowstone, in the Yellowstone National 

 Park, claim that the depth of snow varies from 10 feet in the neigh- 

 borhood of Mammoth Hot Springs to 20 feet at the higher elevations 

 within and adjacent to the park. The light snowfall in the valleys 

 during the winter months is usually speedily evaporated by the 

 Chinook winds, which are met with from Oregon to Nebraska and 

 from the Peace River to Arizona, and arc particularly common in 

 Montana, doing much to modify the climate. The effect of one of these 

 dry, warm winds in raising the temperature and melting the snow is 

 aptly described in the Montana Weather Report for December, 1896: 



On the evening of December 1, 1896, the temperature at Kipp, ISIont., was —13° 

 F. The air was scarcely moving and the sky was clear. Suddenly, over the edge of 

 the mountains in the southwest appeared a great l)ank of black clouds, their outer 

 edges blown into tatters by the wind. In a few minutes a short puff of hot, dry air 

 had reached the plains, and in the following seven minutes the temperature rose 84°. 

 The wind increased in velocity to 25 miles and the temperature rose to 38°. Within 

 twelve hours every vestige of the 30 inches of snow had disappeared, leaving the liills 

 bare and the plains covered with water. 



While the temperature often reaches -40° F. at Havre, which 

 lies in the direct path of the winter storms from the north and north- 

 west, the lowest record at Missoula for twenty-three years is —22^^ F., 

 and in some winters the mercury does not go below the zero point. 

 In many parts of the State the spring months are the most disagreea- 



