132 LANDS OF THE ARID REGION OF THE UNITED STATES. 
the valley is wider, with lower walls, as at Panguitch, Richfield, and Gun- 
nison. An estimate of the amount would be very hazardous; but, judging 
from what is known of similar localities, the amount in the wider valleys 
may be as low as 7 or 8 inches, or as high as 10 or 11. In the narrower 
and deeper valleys it may be between 10 and 12 inches. Upon the plateaus 
it may be as large as 30 to 35 inches. ‘The principal fall is in the winter 
and spring months, from the middle of November to the first of June; and 
in this period at least seven-eighths of the precipitation must be accom- 
plished in the valleys and three-fourths upon the plateaus. There is, how- 
ever, a large amount of variation in the distribution of the monthly falls 
from year to year. No two consecutive years correspond in this respect. 
In 1876 a heavy storm, with great rainfall and snow, occurred in the 
month of October, but in 1875 and 1877 no such storm occurred. In 1875 
many drenching showers occurred in the months of July and August, but 
none occurred at the same months of 1877. In general, however, no sum- 
mer rainfall has ever been known of such extent as to dispense with the 
necessity of irrigation, or even to materially reduce the necessary amount. 
Great variability in the distribution of the fall over different months of the 
year is one of the characteristics of the climate. But whatever the distri- 
bution, it is never such as to affect this one conspicuous feature—that the 
season in which crops must have their chief growth and reach their maturity 
is the dry season. 
Connected with the irrigation of the Sevier Valley is a limiting condi- 
tion, which rarely has to be considered in connection with the lands watered 
by the Bear and Weber Rivers, and which does not enter at all into the 
lands lying about Great Salt Lake. It is the dependence of climate upon 
altitude. There are lands along the upper portions of the forks of the 
Sevier which can be irrigated easily enough, but which are not cultivable 
for grain on account of the shortness of the summer and of the danger of 
frosts during the growth and ripening of the grain. This in turn is directly 
connected with the altitude. At the point where the Sevier leaves its main 
valley and enters the Pavant range, its altitude is 5,050 feet above sea- 
level, At Gunnison it is 5,150 feet. 
