The upper parts of the Little Colorado and Black Rivers, above 7,500 feet, are clear and cold, and well stocked with a native species of small brook trout.

Owing to the generally elevated character of the southeastern section of the Black Mesa Reserve, containing three mountain peaks rising above 10,000 feet, the annual precipitation is decidedly greater than elsewhere on the reserve.  The summer rains are irregular in character, being abundant in some seasons and very scanty in others; but there is always enough rainfall about the extreme head of Black River to make grass, although there is always much hot, dry weather between May and October.  The fall and winter storms are more certain than those of summer, and the parts of the reserve lying above 8,000 feet are usually buried in snow before spring—­frequently with several feet of snow on a level.  The amount of snow increases steadily with increase of altitude.  Some of the winter storms are severe, and on one occasion, while living at an altitude of 7,500 feet, I witnessed a storm during which snow fell continuously for nearly two days.  The weather was perfectly calm at the time, and after the first day the pine trees became so loaded that an almost continual succession of reports were heard from the breaking of large branches.  At the close of the storm there was a measured depth of 26 inches of snow on a level at an altitude of 7,500 feet.  A thousand feet lower, on the plains of the Little Colorado, a few miles to the north, only a foot of snow fell, while at higher altitudes the amount was much greater than that measured.

The summer temperatures are never excessive in this section, and the winters are mild, although at times reaching from 15 to 20 degrees below zero.  Above 7,500 feet, except on sheltered south slopes, snow ordinarily remains on the ground from four to five months in sufficient quantity to practically close this area from winter grazing.  Cattle, and the antelope which once frequented the “Big Mesa” in considerable numbers, appeared to have premonitions of the coming of the first snow in fall.  On one occasion, while stopping at a ranch on the plains of the Little Colorado, just below the border of the Big Mesa country, in November, I was surprised to see hundreds of cattle in an almost endless line coming down from the Mesa, intermingled with occasional bands of antelope.  They were following one of the main trails leading from the mountain out on the plains of the Little Colorado.  Although the sun was shining at the time, there was a slight haziness in the atmosphere, and the ranchmen assured me that this movement of the stock always foretold the approach of a snowstorm.  The following morning the plains around the ranch where I was stopping were covered with six inches of snow, while over a foot of snow covered the mountains.  Bands of half-wild horses ranging on the Big Mesa show more indifference to snow, as they can dig down to the grass; but the depth of snow sometimes increases so rapidly that the horses become “yarded,” and their owners have much difficulty in extricating them.