RECORD OF BLIZZARDS 323 
This factor is the blizzard. Superimposed upon the normal 
winds are the blizzard winds having velocities varying from 10 
miles an hour up to over 60, in consequence of which high winds 
occur with a frequency out of all proportion to what would have 
occurred if there had been no blizzards. 
Thus the shape of the wind curve for Cape Evans shows 
clearly that the blizzard is an abnormal phenomenon superposed 
upon the ordinary meteorological conditions, and the curve for 
Framheim that it does not occur there. 
The cause of the blizzards, their frequency, and the extent 
of country affected by them will be fully discussed in the scientific 
reports of the Expedition; here one is only interested in them 
in so far as they affected the fortunes of the members of the 
Expedition. The following table gives the number of hours 
blizzard winds were recorded at Cape Evans—and the mean 
temperature recorded while the winds were blowing. 
TABLE III. 
Number of blizzards recorded at Cape Evans 
A blizzard is taken as a southerly wind of 25 miles an hour or 
over. 
Number of hours | Number of hours Maximum tem- 
c : perature during 
with record. of blizzard. the blizzards. 
February 1911 612 233 +16°4 
March 744 404 eyat 
April 720 170 Sy 
May 744 72 war ele 
June 720 163 Or) 
July 744 258 gid 
August 726 213 = MOB 
September 720 198 — 46 
October 744 223 — 14 
November 720 215 + 97 
December 720 159 +22°6 
89 +23°8 
January 1912 
February 
March 
744 
