20 Mr. H. F. BlanforcL On the Connexion of the [May 1, 



The North- West Winds after Winter Rainfall. A phenomenon which 

 almost invariably follows a fall of rain and snow on the North- Western 

 Himalaya in the winter and early spring months, and which has 

 been repeatedly described in the Annual Reports on the Meteorology 

 of India,* is a wave of high pressure advancing eastward from the 

 valley of the Indus, accompanied with steady cool north-west winds 

 on the plains. Charts illustrating this phenomenon have been given 

 in several of the Annual Reports on the Meteorology of India, from 

 which I select that of February 26th, 1881, as a very characteristic 

 example (fig. 1). At this season, the snow falls at comparatively 

 low levels (occasionally, though rarely, as in the present year, to 

 below 2,000 feet), and below the snow limit the hill slopes and 

 valleys are cooled by the rainfall. 



In these cases it can hardly be questioned that the north-west 

 wind is simply an outflow of cold air from the hills, the high density 

 of which is the chief cause of the rise of the barometer. On the 

 plains, in the neighbourhood of the hills, it rarely lasts more than a 

 few days ; not longer indeed than it requires to melt the low lying 

 snow and to evaporate the fallen rain, but the phenomenon is of 

 great interest in the bearing that it has on the main topic of this 

 paper, affording an illustration at a low level of that which I con- 

 ceive to operate at a high level on a more lasting and extended 

 scale, later on in the season. 



Summary and Conclusion. 



The principal facts and conclusions set forth in this paper are as 

 follows : 



1st. The experience of recent years affords many instances of an 

 unusually heavy and especially a late fall of snow on the North- 

 Western Himalaya being followed by a prolonged period of drought 

 on the plains of North- Western and Western India. 



2nd. On tabulating the average rainfall of the winter and spring 

 months at the stations of the North-Western Himalaya, year by year, 

 for the last eighteen years, and comparing it with the average rain- 

 fall of the North- Western Provinces in the ensuing summer mon- 

 soon, it is found that with four exceptions an excessive winter pre- 

 cipitation on the hills is followed by a deficient summer rainfall on 

 the plains, and vice versd. Of the four apparent exceptions, two are 

 found to afford a striking support to the first proposition. 



3rd. The west winds which, in Western and Northern India, are 

 characteristic of seasons of drought as abnormal winds, are identical 

 in character with the normal winds of the dry season, and appear to 



See, e.g., Reports for 1878, pp. 129, 130 j 1879, pp. 136, 154 ; 1880, pp. 143, 

 144, in; 1881, pp. 151, 152. 



