Colorado Climatology 9 
the months of July and August, at a time when some of our most 
valuable crops are in need of water. It is then that a supply of 
water stored in our reservoirs, that would otherwise go to waste 
and help increase the damage due to floods lower down, can be im¬ 
pounded and put to a beneficial use to water our best paying crops 
later in the season. This condition arises almost every year, be¬ 
cause our best months for rain are April, May and June, which is 
the time the melting snows cause the rivers and streams to be in a 
flood stage, and as the rains on the plains supply sufficient moisture 
for growing crops, the water then flowing in the streams is available 
for the reservoirs. The storms during the summer months are 
local in character and vary considerably in the amount, from nothing 
to an inch or more, and in their frequency, sometimes one or more 
every day for ten days or two weeks, and then again they are en¬ 
tirely absent, no precipitation falling for three weeks or more. A 
general rain is not usual at this time of the year, the form being that 
of the thunder shower. These local storms are often so frequent 
that several may occur over the same valley or region on the same 
afternoon. The western part of the State and high mountain re¬ 
gions receive most of their precipitation from the westerly winds 
from the Pacific ocean, while east of the mountains the supply ob¬ 
tained from the Gulf of Mexico becomes important. The precipi¬ 
tation during the growing months of the year is about two-thirds of 
that for the entire year, and this is a very important factor, since this 
distribution makes our small supply more effective than it otherwise 
would be. In the crop season when we are subject to a long con¬ 
tinued drouth and many farmers are ruined and destruction is wide¬ 
spread, one cannot fail to see that the state which would fail to de¬ 
velop its irrigation possibilities and reclaim its arid lands would be 
making a great mistake. From the mountain peaks, which collect 
the snows of winter, flow the streams which make crop production a 
certainty. The original source of all our lakes and streams is pre¬ 
cipitation in the form of rain or snow. This is the original water 
supply. The guarantee to the irrigator and farmer, to the irriga¬ 
tion engineer and to the capitalist who finances some of our large 
enterprises, is the information furnished by the rainfall observers 
over the State that there is a sufficient and steady water supply that 
can be depended upon, that we shall know intelligently the amount 
of water available for the use of crops, and that the hydraulic en¬ 
gineer may have data to calculate the supply tributary to the storage 
reservoirs or the streams from which their canals are taken. 
The normal barometer for the Station is 24.992 inches for the 
year. While the Station barometer has been moved two or three 
times, the change in elevation has been very slight and no correction 
lias been applied for this. Only the correction for temperature has 
