• Icefield and glacier
  Canada has passed severe ice ages four times in the past. Asabasca glacier and Columbia Icefields were parts of the huge ice sheet which carved plane of the earth and Rockies as seen today. Asabasca glacier for a certain period of time has flowed into the position of the town of the present Jasper the north, joined other glaciers in addition, and reached the prairie zone in the east and on the tip of Calgary in the south. It required several centuries to flow to this hundreds of km in the distance that reached. The end of the last ice age was just 10,000 years ago, after that, most glaciers in North America keep retreating every year because the amounts of melting in summer are more than the snows accumulated in winter.
  The icefield is formed when the falling snow to the high peaks and the plateau accumulated every year though melted by little and little during summer. When this snow becomes the thickness of about 30 meters, the lower layer part became ice by being compressed. The ice had finally began to flow from the valley when upper snowfall increases and ice becomes thicker. This is a birth of the glacier. The greater part of Columbia Icefield cannot be seen in the course of the snow coach, however, we can see the end part on the surrounding mountains covered with like confectioners' sugar of the cake.
  It is surface of Asabasca Glacier to visit by the snow coach, which is one of glaciers flowing from Columbia Icefield. The speed of Asabasca Glacier, that flows quietly, is too slow to see the movement by eyes. The flow of ice, that forms glacier, looks like river, and the speed differs by the part. Moreover, the ice of the bottom in the glacier, where strong pressure is put, becomes like plastic, and it is possible to flow without cracking even on the rough rocks. The more ice location goes up, the easier it tends to get crack in the ice, and the part where big pressure occurs like three ice cascades (sudden fall part in the glacier) in the upper part of this glacier, and the crevasse will be created. When the glacier flows, its side scoops out and takes away surrounding under the cliff, and the rocks of mountain surface become fragile because of hard temperature change and drop on the glacier. Meanwhile, the bottom ice grinds the rock under that. These large amount of rocks and earth and sand are carried by the glacier, and they are piled up in the side or the end-part of the glacier are called moraine. "Knifed long peak" made of crushed rocks, where the snow coach goes down first, is called lateral moraine (=rocks that piled up on the side of glacier). Rocks, left at the end of the glacier, is called a terminal moraine. A big terminal moraine can be confirmed in the place where the glacier stopped flowing in the valley.
  
  Columbia Icefield
  Gross area: 325km2 biggest in Rockies, Highest altitude: Mount Colombia 3,745m, average altitude: 3,000m, Deepest ice thickness 365m, Average snowfall a year: 7m
  
  Asabasca Glacier
  Gross area: 6km2, Total length: 6km, Thickness of ice: 90-300m, Surface drift velocity: Ice cascade 125m/year, revolution point: 25m/year, Turning point: 15m/year, Altitude: Ice cascade: 2,700m, snow coach turn point: 2,210m, edge point: 1,965m, source: Guide pamphlet of Brewster company.

Crowfoot Glacier	Bow Lake is a glacial lake that thaw water of the glacier was dammed up by the moraine		Claws of the Crowfoot Glacier ..
reduced two from three because of melting	Deep valley with Bow River was used in the movie of "River of No Return" of Marilyn Monroe in 1954. View from Saint-Wapta hill. Road in center is Icefield Parkway, total length 230km.
This valley is a glacial trough where the width cut down by ice under the Cordillera ice sheet with which this ground was covered before.
The Glacier in Columbia Icefield is seen.		Asabasca Glacier.	Snow coach of glacier bus
Mass of huge ice is covered with the earth color adhered to the surface. The ice cascade (sudden fall part in the glacier) is seen in the center.
Side moraine with lateral stripes carried by glacier	Right is Mount Andromeda	The monochrome scenery as far as the eye can reach	Blue ice inside
Ice cascade is upper-left and runs horizontally	People wearing midwinter cloths in August	Ice of 300m thickness below this	Ditch is artificial
Crevasse has as deep as 30m. Caution of no approach. Crevasse in vertical direction
Piling up by both side of the glacier are lateral moraine (side moraine), the rocks that were ground, carried and piled up by the glacier

2007/05/01