Guide books of excursions in Canada1-10 . advance or recession; but when a deluge of snow andice is thrown down in its upper reaches the conditions fora spectacular advance,—a glacier flood—are ice stream flows on more rapidly, its rigid outer portionis cracked and broken, its surface rises, its width increases,and its front is pushed forward. There is, however, astriking difference in the time occupied by the two classesof floods. A river flood passes from the source to themouth of the river in a few hours or a few days, and itseffects are over in a few hours or a few days; but
Guide books of excursions in Canada1-10 . advance or recession; but when a deluge of snow andice is thrown down in its upper reaches the conditions fora spectacular advance,—a glacier flood—are ice stream flows on more rapidly, its rigid outer portionis cracked and broken, its surface rises, its width increases,and its front is pushed forward. There is, however, astriking difference in the time occupied by the two classesof floods. A river flood passes from the source to themouth of the river in a few hours or a few days, and itseffects are over in a few hours or a few days; but the farless mobile ice requires several years for the transmissionof a glacier flood, and its duration is months long, whileyears are required to bring the ice surface back to its pre-flood state. The recent advances of the nine Yakutat bay glaciersjust described may be arranged as follows, when it is seenthat the date of advance is directly related to the lengthof the glacier, the shortest ice tongues advancing first [47]. Length of Glacier. Galiano After 1895 and] before glacier*. 2 or 3 miles (3 to 5 km.) 3 or 4 miles (4 to 6 km.)6 or 7 miles (9 to 11 km.) 8 miles (12-8 km.)10 miles (16 km.)10 miles (16 km.)** 16 or 17 miles (25 to 27 km.) 17 or 18 miles(27 to 29 km.)20 miles (32 km.) * Between Haenke and Hubbard glaciers.** Excluding expanded lobe on Malaspina. Our Alaskan glaciers within the area vigorously shakenin September, 1899, [76.] which subsequently have hadshort vigorous periods of activity, accompanied by severecrevassing and advance, that interrupted a period of stag-nation or slighter activity, are listed below. Some of theseshould certainly be added to the list of nine glaciers whichwe know to have advanced as a result of the earthquakesin 1899. J3 157 £ rtH T33 rt o On00 -as rt-1- ON00
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectgeology, bookyear1913
