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 canon walls.

Then down comes a cataract of rain.