Willie, Richard, Tetsuya, Chris B. and I took a trip to Freel Peak, at almost 11,000 feet the highest point in the Lake Tahoe basin. Chris took this great panarama facing north, with Tahoe and its surrounding forests on the left, the arid (though irrigated) Carson Valley of Nevada on the right, and the alpine Starr Lake near the pass at center. The juxtaposition of forests to the west and desert to the east show how the effects of mountains dominate the climate of the western USA. Storms advect eastward from the Pacific Ocean. As the Sierra Nevada forces the moist air upwards, the air cools to its dewpoint and drops rain and snow over the western slopes of the Sierra, and over Tahoe. Over 10,000 years ago, this moisture also fed the glaciers which carved out many of the lakes and hanging valleys in the Tahoe basin and elsewhere in the Sierra Nevada. After a storm loses a good deal of its moisture to the Sierra Nevada, the storm flows eastward, down the leeward slope of the mountain range, gets compressed as the air pressure increases, and heats up. Since the air is now drier than it had been during its trip up the western slope of the Sierras, there is less moisture to evaporate than had been condensed over the western slope, so the temperature of the air east of the mountains rises above what it had been at the same altitude west of the mountains. The result is the hot, dry desert of Nevada, easily seen in the brown Carson Valley. Even the glacial history of the region was heavily affected by this gradient in moisture: the Sierras and are full of glacial-carved lakes, valleys, and moraines, while the mountains to the east of Carson Valley, though nearly as high, did not receive enough moisture to feed glaciers, and thus do not show these glacial-carved features. 
Chris was really on a role with these beautiful panoramas he shot during the trip. This one was taken from Maggie's peak, looking northeast toward South Lake Tahoe. We accessed this peak from the top of Emerald Bay, and at the summit ran into a UC Berkeley geomorphology class being taught by Prof. Deitrich! Naturally we hung out for this fascinating lecture in the field, and, as we were freeloading without paying tuition, it's only right that I share the learning here. Cascade Lake is in the foreground. This lake exists at the furthest extent of an ancient glacier, which dropped down off the mountain and deposited its terminal moraine at Cascade Lake's northern (left) end, and which built up lateral moraines that now confine both sides of the lake (the lateral moraines are the hills which run along the long axis of the lake). Fallen Leaf Lake (at far right) is a larger lake formed in the same way; the lateral moraines of the glacier that formed it are still visible as forested hills on the lake's flanks, and the terminal moraine forms the isthmus between Fallen Leaf Lake and Lake Tahoe. That isthmus is now a relatively flat, marshy regions atop which the city of South Lake Tahoe and the casinos of Stateline have been built. The meadows and marshes along the stream flowing from Fallen Leaf to Tahoe hold nice campsites and flat-ground trails which should make scenic (and easy) cross-country skiing in the wintertime!
At the far left of the photo is Emerald Bay. This was also likely formed by a glacier ending in the lake. The lateral moraines (hills) which confine the long axis of the lake are readily visible. There does not seem to be a terminal moraine, however. This may have been due to the lake slowly rising in level during a wet period, flooding over the terminal moraine, and eventually eroding it away (as the Mediterranean eroded the Bhosperous during what may have been the Great Flood of the Bible). Alternatively, Prof. Dietrich said the lack of terminal moraine may be due to a lake seiche (tsunami) resulting from the Meek's Bay landslide that occurred many thousands of years ago on Tahoe's western shore. The landslide in the lake may have caused a long wave that washed over the low-lying moraine, eroded it away, and thereby dug a connection between Tahoe and Emerald Bay.
I've got to include a photo of my buddies at the summit!
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