| Professor Fergusson at the
Fergusson Meteorograph at Mt. Rose Observatory. 10,090 Feet Click photo to see full-sized. |
From that day the work has been carried on with a vigor and enthusiasm that are thrilling in their inspiration. An improved instrument was added that recorded temperatures on a self-registering roll, all fluctuations, and the highest and lowest temperatures, wind-pressures, all variations in humidity, temperature, and air pressure as well as the directions and the velocity of the wind for periods of seventy days and more. This instrument was the achievement of Professor S.P. Fergusson, for many years a pioneer worker in mountain meteorology at Blue Hill Observatory and an associate of Professor Church at the Mount Rose Observatory, which has now become a part of the University of Nevada.
After two winters' work it was discovered, on making comparisons with the records at the Central Weather Station at Reno, 6268 feet below, that frost forecast could probably be made on Mt. Rose from twenty-four to forty-eight hours in advance of the appearance of the frost in the lower levels, provided the weather current was traveling in its normal course eastward from the coast.
[!-- Note Anchor 12 --][Footnote 12: Since this was written Professor McAdie has been appointed to the chair of Meteorology at Harvard University.]
Second only in importance was the discovery and photographic recording of evidence of the value of timber high up on mountains, and especially on the lips of canyons, for holding the snow until late in the season.
This latter phase of the Observatory's work has developed into a most novel and valuable contribution to practical forestry and conservation of water, under Dr. Church's clear and logical direction. At Contact Pass, 9000 feet elevation, and at the base of the mountain, supplementary stations have been established, where measurements of snow depth and density, the evaporation of snow, and temperatures within the snow have been taken. Lake Tahoe, with its seventy miles of coast line also affords ready access throughout the winter, by means of motor boat, snow-shoes and explorer's camp, to forests of various types and densities where snow measurements of the highest importance have been made.
Delicate instruments of measurement and weight, etc., have been invented by Dr. Church and his associates to meet the needs as they have arisen, and continuous observations for several years seem to justify the following general conclusions. These are quoted from a bulletin by Dr. Church, issued by the International Irrigation Congress.
The conservation of snow is dependent on mountains and forests and is most complete where these two factors are combined. The mountain range is not only the recipient of more snow than the plain or the valley at its base, but in consequence of the lower temperature prevailing on its slopes the snow there melts more slowly.
However, mountains, because of their elevation, are exposed to the sweep of violent winds which not only blow the snow in considerable quantities to lower levels, where the temperature is higher, but also dissipate and evaporate the snow to a wasteful degree. The southern slopes, also, are so tilted as to be more completely exposed to the direct rays of the sun, and in the Sierra Nevada and probably elsewhere are subjected to the persistent action of the prevailing southwest wind.
On the other hand, the mountain mass, by breaking the force of the wind, causes much of the drifting snow to pile up on its lee slope and at the base of its cliffs, where it finds comparative shelter from the wind and sun.
Forests, also, conserve the snow. In wind-swept regions, they break the force of the wind, catching the snow and holding it in position even on the windward slopes of the mountains. On the lower slopes, where the wind is less violent, the forests catch the falling snow directly in proportion to their openness, but conserve it after it has fallen directly in proportion to their density. This phenomenon is due to the crowns of the trees, which catch the falling snow and expose it to rapid evaporation in the open air but likewise shut out the sun and wind from the snow that has succeeded in passing through the forest crowns to the ground. Both mountains and forests, therefore, are to a certain extent wasters of snow—the mountains because they are partially exposed to sun and wind; the trees, because they catch a portion of the falling snow on their branches and expose it to rapid disintegration. However, the mountains by their mass and elevation conserve immeasurably more snow than they waste, and forested areas conserve far more snow than unforested. If the unforested mountain slopes can be covered with timber, much of the waste now occurring on them can be prevented, and by thinning the denser forests the source of waste in them also can be checked.
| The Fergusson Metrograph
on the summit of Mt. Rose, wrecked by snow "feathers," some of which were six feet long. Click photo to see full-sized. |
The experiences met with by the voluntary band of observers to secure the data needed in their work are romantic in the extreme. An average winter trip requires from a day and a half to two days and a half from Reno. From the base of the mountain the ascent must be made on snow-shoes. When work first began there was no building on the summit, and no shelter station on the way. Imagine these brave fellows, daring the storms and blizzards and fierce temperatures of winter calmly ascending these rugged and steep slopes, in the face of every kind of winter threat, merely to make scientific observations. In March, 1906, Professor Johnson and Dr. Rudolph spent the night at timber-line in a pit dug in the snow to obtain protection from a gale, at the temperature of 5° Fahr. below zero, and fought their way to the summit. But so withering was the gale at that altitude even at mid-day, that a precipitate retreat was made to avoid freezing. The faces of the climbers showed plainly the punishment received. Three days later Dr. Church attempted to rescue the record just as the storm was passing. He made his way in an impenetrable fog to 10,000 feet, when the snow and ice-crystals deposited by the storm in a state of unstable equilibrium on crust and trees were hurled by a sudden gale high into the air in a blinding blizzard. During his retreat he wandered into the wildest part of the mountain before he escaped from the skirts of the storm.