through May there is an average of about four gales each month. 

 At Verkhoyansk the monsoonal character is also reflected in the 

 winds aloft. 



In the winter at 3,000 feet, 56 percent of the observed direc- 

 tions are south to southwest at about 10 m. p. h. At 10,000 feet 

 the quadrant having the greatest percentage is to the southwest 

 with 37 percent. Low pressure areas seldom invade this con- 

 tinental area of eastern Siberia because of the uninterrupted 

 strength of the anticyclone. Any cyclonic activity is fairly well 

 confined to the region between the Polar Anticyclone and the ridge 

 of high pressure in eastern Siberia. The passage of cyclones in 

 the region referred to above would affect the wind system along 

 the northern quadrant of the Siberian anticyclone. Northwest 

 winds follow in the wake of these cyclones and this could account 

 for the fact that of the observed winds at 10,000 feet at Verk- 

 hoyansk 19 percent are northwest. 



There is insuflficient information about conditions above to draw 

 any conclusions, but from the few available observations it ap- 

 pears that practically all directions are represented. At 3,000 

 feet southerly winds are less predominant in spring; 30 percent 

 are south to southwest at 11 m. p. h. There is a secondary direc- 

 tion of greatest frequency from the northeast to north-northeast 

 of 25 percent. At 10,000 feet, in spring, 50 percent are from that 

 90° quadrant from south-southwest to west-northwest, while 40 

 percent are from that 90° quadrant from north to east at about 

 12 m. p. h. At this elevation those winds having the least fre- 

 quency are those with a southeasterly component. Summer brings 

 a reversal of the wind flow, at which time the thermal low develops 

 over the interior and winds become northerly at Verkhoyansk. 



At 3,000 feet 30 percent are north-northeast to east-northeast 

 with a secondary maximum of frequency from south-southwest to 

 west-southwest. At 10,000 feet, however, 55 percent prevail from 

 the northwest to northeast, and at 20,000 feet 64 percent are west 

 to north. The great depth of the northerly current in summer is 

 no doubt dependent upon the fact that at that time Verkhoyansk 

 is located along the pressure gradient between the relatively high 

 pressure of the polar region and the low pressure of the Asiatic 

 continent. Autumn again brings southwesterly winds at 3,000 

 feet with 55 percent south-southwest to west. A gradual veering 

 of the wind takes place with elevation, and at 10,000 feet 46 per- 

 cent of the observed winds are from southwest to west-northwest 

 at 14 m. p. h. 



102 



