RUSSELL.] 
CLIMATE. 19 
they are frequently hot, and to one facing them seem the breath of 
a furnace. On the broad plains miniature whirlwinds are of fre- 
|| quent occurrence, particularly on hot afternoons, and the dust carried 
upward by them forms tall columns with hollow centers, in which, 
when they are near the observer, a spiral motion can be discovered. 
These dust columns are sometimes 2,000 or 3,000 feet high, and are a 
characteristic feature of the parched desert-like plain when heated by 
the intense summer sun. 
Owing to the great extent of the plains, their variations in altitude, 
the influence of the adjacent mountains, and other factors, there are 
many local variations in the climatic conditions. The most marked 
differences are in temperature and in the length of time the land is 
snow-covered. These variations are most marked in the broad, nearly 
flat areas forming the general surface and in the limited tracts of level 
land in the canyons and canyon-like valle} T s. In the canyon of Snake 
River and its tributaries below Shoshone Falls the atmospheric condi- 
tions are markedly different from those on the surfaces of the adjacent 
plains. In the canyons the temperature in summer, owing to the 
helter from the winds afforded by the bordering precipices and the 
reflected and radiated heat from the black rocks, is usually much 
higher than on the open plains. Cool breezes frequently Woav along 
the river, however, tempering the intense heat. Again, in winter, 
3wing largely to the ameliorating influence of tho river, as well as the 
protection afforded by the bordering cliffs from the freezing blasts 
:hat sweep over the plains, the mean daily and monthly temperatures 
n the canyon are considerably higher than on the neighboring undis- 
sected plain. Snow seldom lies on the ground in the canyon bottoms 
x>r more than a few days at a time. 
The canyons furnish many favorable places for orchards, vineyards, 
md gardens, not only on account of the intense heat and strong light 
luring the growing season, when they are essentially hothouses, but 
)ecause water from springs with a temperature of about 60° F. can 
Tequemly be had for irrigation. 
In brief, the Snake River plains present a typical illustration of an 
nsular or continental climate, such as is characteristic of regions of 
nild relief, remote from the tempering influences of the ocean, and 
leprived of their requisite share of moisture by the presence of lofty 
nountains in the path of the prevailing winds. 
One result of the climatic conditions, and especially of the dryness 
f the air, is the healthfulness of the land. So far as I am able to 
udge, it is a region exceedingly favorable to persons suffering from 
isease of the lungs. 
To lovers of nature and all who rejoice in scenes of natural wildness 
nmodifled, or what is too frequently essentially the same thing, 
egg inmarred by the hand of man, the plains of southern Idaho present 
