4.4.8 REPORT—1904. 
general occasional rain required for the wheat and other cold-weather crops of 
Northern India, 
The storms of the hot weather are local disturbances of very limited extent, 
usually in large areas of slight depression, and are occasionally of remarkable 
intensity and great violence. In the areas to which the local sea winds of 
the period extend (more especially Bengal and Assam) they occur chiefly as local 
thunderstorms with violent winds and brief heavy downpours of rain, but some- 
times as tornadoes rivalling those of certain districts of the United States in inten- 
sity and destructiveness. In the dry interior they occur as dust-storms, usually 
without rain, and are most violent in the driest districts, including Sind, the 
Punjab, and Rajputana. Occasionally, when the convective movement is especially 
vigorous, they develop into hailstorms of great intensity. The rainfall accom- 
panying these hot-weather storms is of little general agricultural value except in 
the tea districts of Assam and Bengal. 
Finally, the wet monsoon is characterised by the frequent occurrence of 
cyclonic storms of every degree of intensity and of very varying extent. The 
great majority of them originate in sea areas of nearly uniform temperature as 
disturbances in a massive current highly charged with aqueous vapour and subject 
to large variations of intensity and extension. The more prominent features of 
these storms, more especially of the most violent, including the hurricane winds, 
excessive rainfall, and the phenomena of the central calm and the accompanying 
storm wave, are too well known to require description. The chief importance of 
these storms, of which an average of about ten (of different degrees of intensity) 
occur every year during this period, arises from the manner in which they modify 
the distribution of the rainfall, discharging it abundantly over the districts traversed 
by the storms at the expense of the districts outside of their field. 
The most important and variable feature of the weather in India from the 
practical standpoint is rainfall. Its value depends upon its amount and occurrence 
in relation to the needs of the staple crops. The measurement of rainfall is 
carried out, on a uniform system, at upwards of 2,500 rain-gauge stations. The 
average distribution of rainfall, month by month and for each season, has been 
determined from the data of about 2,000 stations. It should, however, be recog- 
nised that the probability that the rainfall will conform exactly to this distri- 
bution in any year is nil. Average rainfall charts represent a distribution about 
which the actual varies from district to district more or less considerably, the 
local variation for prolonged periods being practically compensatory. Such mean 
or normal data and charts are undoubtedly of value, more especially for the deter- 
mination of rainfall anomalies and their relations to pressure, temperature, and 
other anomalies. There is apparently a tendency to assign a greater value to these 
charts of mean rainfall distribution than they deserve. Charts showing the 
amount and time distribution of the rainfall best suited for the requirements of 
the staple crops would—for India at least—be more interesting and valuable. 
This is a work that I regret has, for various reasons, not yet been carried out by 
the Indian Meteorological Department. 
In most regions in India a moderate variation (positive or negative) in the 
amount of the rainfall is of comparatively small importance, more especially if the 
precipitation occurs in amount and at intervals suited to the requirements of the 
crops. During the thirty-year period 1874-1903 there were six years in which 
the distribution of rainfall affected to a serious extent the crop returns over large 
areas, and the rainfall was not compensatory. In four of these years the drought 
was so severe and widely spread as to occasion famine, with its attendant calamities, 
over large areas. Severe droughts and famines occur at very irregular intervals, 
A noteworthy feature is that they frequently follow in pairs separated by intervals 
of two to four years. 
The previous statement of the meteorology of India has indicated the chief 
conditions which affect the crop returns seriously or disastrously over large areas 
in India. They may be summed up briefly as follows ;— 
(az) The dry monsoon. Absence or unusual feebleness of cold-weather storms. 
(6) The wet monsoon, General feebleness of the monsoon current, due either 
