Thursday, July 05, 2007

Sucharitha's trip to Alaska

Day 2 : The Chugach Mountains and Prince William Sound

Prince William Sound with its 3,000 miles of shoreline is surrounded by the Chugach Mountains to the east, west and north. Fifty-mile long Montague Island and several smaller islands form natural breakwaters between the Sound and the Gulf of Alaska. Between the barrier islands stretch underwater sills separating the Sound's deep waters from the much shallower waters of the Gulf. Deep water renewal occurs during the winter when cold winds from interior Alaska cool the surface waters causing them to sink, while the warmer bottom water rises to the surface bringing rich nutrients which support huge plankton blooms in the spring.

Millions of years of glaciation gradually carved away a coastal plateau creating the sound with its many tributary fiords and passageways, islands and rocky shores. Fewer than 10,000 people live in the three towns-Whittier, Valdez, and Cordova- and two native villages-Chenega and Tatitlek situated on the shores of the Sound. Because the Sound was formed by millions of years of glaciation, its shorelines are heavily indented by deep fiords and many smaller bays. No roads connect these communities.


Glaciation of the Chugach Mountains and Prince William Sound

Recently, glaciologists examining sediments in the Gulf of Alaska have discovered evidence of glaciation over the past 5 million years. They suspect the area has been glaciated for nearly 15 million years. Few other places on the planet have experienced such a prolonged period of glaciation. In cooler periods, glaciers covered all of the coastal plateau. During warmer periods, they retreated to the mountains.

About 20,000 years ago, the Earth's climate cooled and the last of the great Pleistocene ice age glaciers advanced down from the Chugach Mountains. Glaciers formed in the streambeds of the coastal plateau and carved deep valleys. When the glaciers receded about 12,000 years ago, they had scoured the Earth's crust down to the granite roots of the Chugach range and scoured out deep fjords (glacially carved valleys filled with sea water) creating Prince William Sound and the rugged, glacially sculpted Chugach Mountains.

Prince William Sound, nestled in the coastal arc of Alaska's Chugach Mountain Range, has over 20 glaciers terminating at sea level; numerous others cling to precipitous mountainsides.These glaciers form because warm, low pressure systems sweeping in off the Pacific Ocean in the winter encounter the high mountains, rise, cool and deposit their excess moisture as snow. More snow falls in the long winter than melts during the short summer. In fact, in the higher elevations of the Chugach Mountains it is not uncommon for snow to fall twelve months of the year. The thick, accumulating snow layers compress into ice which gradually flows down to the sea as glaciers.

Enjoy the pictures posted below for Prince William Sound.
I had great fun !!!!!!

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