THE CONTINENTAL GLACIERS OF POLAR REGIONS 285 



vation of temperature within the column. Eventually the warm 

 air now charged with water vapor reaches the ice surface, is at 

 once chilled, and its burden of moisture precipitated in the form of 

 fine snow needles, the so-called " frost snow," which in accompani- 

 ment to the sudden elevation of temperature is precipitated at the 

 termination of a blizzard. 



The warming of the air has, however, had the effect of damping 

 as it were, the engine stroke, and, as the process is continued, to 

 start a reverse or upward current within the chimney of the anti- 

 cyclone. The blizzard is thus suddenly ended in a precipitation 

 of the snow, which by changing the latent heat of condensation 

 to sensible heat tends to increase this counter current. 



The glacier broom. During the calm which succeeds to the 

 blizzard, heat is once more abstracted from the surface air layer, 

 and a new outwardly directed engine stroke is begun. The tem- 

 pest which later develops acts as a gigantic centrifugal broom which 



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 oS3C3 ^o^^ 



FIG. 313. Snow deltas about the margins of the Fan glacier outlet of Greenland 



(after Chamberlin) . 



sweeps out to the margins of the glacier all portions of the latest 

 snowfall which have not become firmly attached to the ice surface. 

 The sweepings piled up about the margin of continental glaciers 

 have been described as fringing glaciers, or the glacial fringe. The 

 northern coast of Greenland and Grant Land are bordered by a 

 fringe of this nature (plate 14 A, and Fig. 315, p. 288). It is by the 



