324 SCOTT'S LAST EXPEDITION 
It is only necessary to study this table for a few minutes to 
realise the conditions which had to be faced, and it explains why 
the fortunes of the sledging parties were affected so largely by 
the weather. 
With regard to the extent of the country subjected to bliz- 
zards we cannot of course be very precise. Judging from Cap- 
tain Amundsen’s report they did not occur at Framheim, nor on 
the route he took to the Pole. Very high winds were occasionally 
experienced at Cape Adare, but they were in no way connected 
with our blizzards; as a rule when a blizzard was blowing at 
Cape Evans there was only a light southerly wind at Cape Adare. 
We know that typical blizzards were encountered at all points 
of Captain Scott’s route as far as the Beardmore Glacier. 
Whether the winds met with on the Plateau were connected with 
blizzards on the Barrier cannot be decided until a more thorough 
study has been made of the meteorological records kept by the 
different sledging parties. From the data at present available 
there appears no doubt that blizzards were confined almost 
entirely to the western half of the Ross Barrier. 
The cause of the blizzards, and why they occur only over the 
western half of the Barrier, are questions which cannot at pres- 
ent be answered with any certainty. It appears however that the 
chief factors are the following: The air over the Barrier cools 
down much more than the air over the Ross Sea, and in conse- 
quence there is a region of relatively low pressure over the sea. 
Into this region the air from the Barrier tends to move, but 
owing to the large deflecting force of the earth’s rotation so near 
to the Pole, the air cannot move from south to north but is driven 
towards the west. 
The western boundary of the Barrier, however, is a range of 
lofty mountains which stop the westerly motion entirely. In 
consequence the pressure distribution becomes unstable and the 
tension is removed by a rush of air along the Western Moun- 
tains, through McMurdo Sound out into the Ross Sea. The 
evidence on which this explanation is based will be given in the 
scientific report. 
In order to give some idea of the intensity of the blizzards 
a few records of one of the self-registering anemometer are re- 
produced. These records were taken by an instrument at the hut, 
and as the hut had been built in the most sheltered place avail- 
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