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John Muir on Sierra Thunder-Storms![]() THE weather of spring and summer in the middle region of the Sierra is usually well flecked with rains and light dustings of snow, most of which are far too obviously joyful and life-giving to be regarded as storms; and in the picturesque beauty and clearness of outlines of their clouds they offer striking contrasts to those boundless, all-embracing cloud-mantles of the storms of winter. The smallest and most perfectly individualized specimens present a richly modeled cumulous cloud rising above the dark woods, about 11 A.M., swelling with a visible motion straight up into the calm, sunny sky to a height of 12,000 to 14,000 feet above the sea, its white, pearly bosses relieved by gray and pale purple shadows in the hollows, and showing outlines as keenly defined as those of the glacier-polished domes. In less than an hour it attains full development and stands poised in the blazing sunshine like some colossal mountain, as beautiful in form and finish as if it were to become a permanent addition to the landscape. Presently a thunderbolt crashes through the crisp air, ringing like steel on steel, sharp and clear, its startling detonation breaking into a spray of echoes against the cliffs and caņon walls. Then down comes a cataract of rain .
The big drops sift through the pine-needles, plash and patter on the
granite pavements, and pour down the sides of ridges and domes in a network
of gray, bubbling rills. In a few minutes the cloud withers to a mesh
of dim filaments and disappears, leaving the sky perfectly clear and bright,
every dust-particle wiped and washed out of it. Everything is refreshed
and invigorated, a steam of fragrance rises, and the storm is finished--one
cloud, one lightning-stroke, and one dash of rain. This is the Sierra
mid-summer thunder-storm reduced to its lowest terms. But some of them
attain much larger proportions, and assume a grandeur and energy of expression
hardly surpassed by those bred in the depths of winter, producing those
sudden floods called "cloud-bursts," which are local, and to a considerable
extent periodical, for they appear nearly every day about the same time
for weeks, usually about eleven o'clock, and lasting from five minutes
to an hour or two. One soon becomes so accustomed to see them that the
noon sky seems empty and abandoned without them, as if Nature were forgetting
something. When the glorious pearl and alabaster clouds of these noonday
storms are being built I never give attention to anything else. No mountain
or mountain-range, however divinely clothed with light, has a more enduring
charm than those fleeting mountains of the sky--floating fountains bearing
water for every well, the angels of the streams and lakes; brooding in
the deep azure, or sweeping softly along the ground over ridge and dome,
over meadow, over forest, over garden and grove; lingering with cooling
shadows, refreshing every flower, and soothing rugged rock-brows with
a gentleness of touch and gesture wholly divine.
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