PRECIPITATION 29 



snow-clouds in December and January for some distance inland. Probably 

 when this system is accelerated, as it would be in autumn and winter, it 

 may bring a great deal of snow to the eastern part of this plateau. 



(h) Cyclonic surface winds, portions of large cyclones N. of Ross Sea. 



(c) The N.W. high-level wind. This is part of a vast circulation. As already 

 stated, we observed it frequently rolling in great masses of snow-cloud as 

 alto-cumulus, alto-stratus, and on one occasion apparently cumulus, from 

 the N.W. This great air current is the one which supplies the 

 " Temperature Pole " with air to replenish the supplies which have flowed 

 away from it down-hill as blizzard winds, modified in places by local 

 conditions of the physiographic relief of the plateau. 



There can be no doubt that when accelerated during spring or autumn, when the 

 surface of the plateau is colder than on the occasion of our visit, it must bring 

 quantities of snow with it to feed the inland Magnetic Pole Plateau, and even to take 

 with it, as delicate ice needles, to the " Temperature Pole." 



Thus the activity of great glaciers like the Reeves, Larsen, and David is probably 

 due to this efficient double snowfall, the snow being partly derived from the northern 

 part of Ross Sea, partly from the Southern Ocean, near Adelie Land. 



"We may now glance briefly at the snow supplies of the King Edward VII. Plateau 

 and the region near the South Pole itself Scott and Amundsen have recorded that 

 at the South Pole itself the snow is soft to a great depth, so that a tent pole could 

 be thrust six feet into it, and in doing this no evidence whatever of any stratification 

 was detected. Evidently, therefore, there is no very considerable sublimation and no 

 thawing taking place at the South Pole, and on the whole the area cannot be much 

 disturbed by winds. It appears to be the eye of the great anticyclone. Thin hazes, 

 described as " a light fine vaporous curtain," kept coming and going while 

 Amundsen was at the South Pole from December 14-17.* 



Possibly these mists or hazes of ice crystals were derived from vapour sublimed 

 from the surrounding snowfields, though, of course, it is equally possible that it may 

 have been transported by the high-level cyclone all the way from the Southern Ocean. 



It is of great interest to note that from 80° S. to 88° S. Amundsen met with new 

 falling snow derived from surface ivinds. 



On November 27, 1911, just S. of 86° S. he encountered mist and snowfall, 

 followed by dense fog and fine falling snow on November 28, the fog being described 

 as " as thick as gruel." From November 29 to December 3, a strong S.E. blizzard 

 brought new-falling snow in lat. 86° 47' S. 



* "The South Polo," vol. ii. p. 117. " Often — very often indeed — on this part of the plateau, to the 

 south of 88° 25', we had difficulty in getting snow good enough — that is solid enough — for cutting blocks. 

 The snow up here seemed to have fallen very quietly, in light breezes or calms. We could thrust the tent 

 pole, which was 6 feet long, right down without meeting resistance, which showed that there was no hard 

 layer of snow. The surface was perfectly level ; there was not a sign of sastrugi in any direction." 



