Report of Mr. John Muir

To

A. F. Rodgers, Asst. U.S.C.S

May 1875

San Francisco, Cal.
May 6, 1875

A.F. Rodgers
Assistant, U.S.C.S.

Dear Sir,

In accordance with your request I have the pleasure to make the following report of my accent of Mt. Shasta on the 30th of April, two days after visiting the summit with you.

After you left camp on the 29th, I moved such provisions and blankets as were necessary for one night to the upper or summer camping ground, so as to be the better able to reach the summit the next day at an early hour.

Jerome Fay returned to me in camp with Cistern Barometer No. 1544 as directed by you with which I started for Shasta Summit on the morning of April 30th at 3:30 A.M. in company with Fay – the Barometer was observed at 9 A.M., 12 Noon, and 3 P.M.

A violent storm broke upon the mountain immediately after making the last observation, which perhaps made it less dangerous to remain all night upon the summit than to attempt the descent, and because this may be regarded as a fair specimen of the storms developed at this season of the year among the summits of the Sierra Nevada in general, I will trace the principal phases of its growth adding such illustrative incidents as may help to bring out its peculiar characteristics.

On reaching the summit at 7:30 A.M. we observed a level field of white unbeaten clouds, lying some five or six thousand feet beneath us, upon the lava plains towards Lassen’s Peak, and covering an area of two or three hundred square miles. In shape and color it resembled the fog fields of the Ocean, as seen in fine weather from the top of Tamalpais [Mt. Tamalpais in Marin County, north of the Golden Gate], but firmer and closer in texture – About 12 noon clouds began to appear down in Shasta Valley, huge bulging cumuli developing with a visible squirming motion, in ranks and clusters like toadstools from a level base of the same material -- These slowly extending Southward around both sides of Mt. Shasta, at length united with the older field mentioned above, and thus encircled the mountain with one continuous cloud-zone, while the entire dome of the sky above was wholly cloudless and sunfull – A few loose wooly streamers were drawn out from a few of the cloud summits, but most exhibited remarkably clear and hard outlines. While they constantly developed to greater individuality in form and general physiognomy. One colossal master cone grew up out of the general cloud plain, just as Mt. Shasta rises out of its plains of lava, its summit was so near and its fine lustrous bosses seemed so hard and rock-like, we fancied we might leap upon it from where we stood and reach the plain by clambering down its sides – The topography of this extensive cloud land was brought out with great forcibleness by pale blue and purple shadows filling its hollows and valleys and contrasting with its glowing pearly heights. About 1:30 P.M. fibrous translucent cloud films began to drift directly over the summit from North to South. They were too thin to intercept much of the sunshine and were drawn out in long webs like carded wool, some were trailed across the rocks and stones (?), while others were drifted a hundred feet or more above the highest peaks of the summit, these films constituted the first discernible beginnings of the storm that broke upon the Summit. The cloud zone beneath having been described as indicating the relative conditions of the lower air strata out of which the material for the summit storm was derived, the upper clouds were evidently produced by the chilling of the air from its own expansion on its being deflected upward off the slopes of the mountain. They steadily increased in thickness forming an opaque ill-defined embankment upon the Southern rim of the cone in which hail and soon afterwards snow was developed, some of which was carried off its dark fringes into the sunshine that still bathed the South rim on which we stood. Just after completing the 3 P.M. observations the storm broke into full bloom. The thermometer falling from 44 to 22 in a few minutes – Snow filled the air causing darkness like night, the wind blew with inconceivable violence and loud thunder mingled with the general uproar. Having succeeded in boxing the instruments, we began to break our way down the shattered ridge that bounds the Summit on the East a few minutes after 3 P.M. The irregular snow ridge a mile and a half long flanked by precipices on one side and by the ice slopes of Whitney Glacier on the other, which had to be passed before beginning the main descent, was so hidden in darkness of the storm, and so violently wind-swept we concluded to remain at the hot springs trusting to their warmth to keep us from freezing – The thunder was heard only about an hour at the beginning of the storm; the detonations being very harsh and loud although somewhat muffled and rounded off on the edges by passing through the snow-filled air – no lightning was at any time observed. The snow fell steadily for five hours with a lavishness not easily conceived about two feet fell at the Summit while only three inches fell at the camp at an elevation of about 8,500 feet, although the great drifting that took place made these measurements far from exact. The lowest point reached by the snow was about 7,000 feet above the sea level. From the time the storm broke to its end there was not a single pause or visible abatement either in the speed of the wind, or the snow fall, or of the attendant darkness. Its development was deliberate and gentle – the slow growth and massing of clouds beneath the wearing and filling of light cloud tissue above, then the roar of the wind, the crack of thunder, and the darkening flight of hail and snow – It decay was not less sudden, the clouds vanished, not a snow crystal was left in the sky, and the stars shone out with pure and tranquil radiance. The temperature continued to fall until morning as evinced by the freezing of our breath and the snow which first was kept soft by the hot vapors of the fumaroles among which we lay – I very much regret my inability to observe the thermometer throughout the night, my exhausted and benumbed condition making it impossible. We suffered greatly from the frost wind, at the same time we were uncomfortably warm where touched by the hot gases and lava, the violent winds shearing off all the vapor and gas jets close to the ground, leaving the climate an eighth of an inch above it intensely cold. At 8 A.M. we began the descent towards camp on the 1st of May, and though suffering from exhaustion, from want of sleep and food, and from exposure, we reached camp at 10 A.M., having sustained no other injury excepting the slight freezing of our toes which caused a good deal of pain. In six hours more we were convalescing in the warm zone at the base of the mountain among the spring flowers.

I have the honor to be Yours etc.

John Muir