434 SNOWSTORMS IN THE TRANSVAAL. 



over the Transvaal, and the sky was cloudy over the region 

 occupied by the secondary depression, with passing showers 

 in places. At Swakopmund, on the west coast, there was 

 evidence of the approach of a high pressure system. At 9 a.m. 

 on Sunday, August 15th, the barometer was rising generally, 

 but pressure was still low along the east coast. Over the 

 west pressure was much higher, being highest near Cape 

 Town. Fine weather prevailed over the Transvaal, but with 

 very cold strong winds from the south and west. The sky 

 was cloudy over Natal, and rain fell at the Cape. 



On the morning of the i6th the region of high pressure had 

 travelled eastwards, so that the highest pressures were over 

 the south of Cape Colony and along the Natal coast. The 

 direction of the isobars was from east to west over the land. 

 Strong easterly winds prevailed over the Transvaal. The 

 weather was fine and cold during the day, but at night the 

 humidity of the atmosphere increased and the sky became over- 

 cast. Rain had fallen along the south coast. The high pres- 

 sure region continued its motion up the Natal coast, and also 

 along the east. About midnight, on the i6th, a general pre- 

 cipitation began over the Transvaal — snow over the 5,000 foot 

 level, and steady cold rain at a less altitude. This continued 

 until the early hours of Wednesday, August i8th. The 

 weather map at 9 a.m. on this day showed that the high pres- 

 sure region had receded from the east coast. The fall of 

 snow had ceased and the weather was clearing over the High 

 Veld, but rain was still falling in the extreme north and east 

 of the Transvaal. 



With the exception of some very light rainfall over the 

 south-western Transvaal, no rain fell over eastern South Africa 

 during the time that the barometer was low there. Strong 

 northerly winds prevailed, at first followed by a cold, dry 

 southerly gale, which produced a sharp frost, and it was not 

 until the wind had moved round to the east that the humidity 

 of the atmosphere began to increase and some precipitation of 

 rain or snow seemed probable. Thus the great fall of snow 

 and rain cannot be associated with the existence of a region 

 of low pressure over eastern South Africa, but rather with 

 the rapid approach of a high pressure system tozvards a region 

 over which a low pressure system had previously lain. 



In the writer's experience it has always been found that any 

 widespread rainfall over eastern South Africa is associated 

 with a rising barometer. When the synoptic chart shows that 

 pressure is highest along the south and south-east coasts of 

 South Africa, and lowest over Southern Rhodesia and Bechu- 

 analand, with the isobars over Natal running from N.E. to 

 S.W., then moisture-bearing winds from an easterly quaiter 

 will set in. Should this distribution occur during the summer 

 months a general rainfall will probably be experienced: m the 

 winter months the result may only be the occurrence of damp 

 mists and fogs along the eastern border of the Transvaal, with 

 occasionally some light rain. 



A quotation from an article on " Argentine Weather," in the 

 United States IV cat her Rcz'iczc. of March, 1909. is of in- 



