Voiv. 6, 1920 
GEOPHYSICS: C. F. MARVIN 
565 
in the National and other forested regions. They are distributed principally to Forest 
Service officials and others charged with forest protection. 
The warnings aid in the protection of the forests by enabling crews and apparatus to 
be ready for action. Numerous testimonials of their value have been received, several 
in the form of resolutions passed at the conventions of Forestry Associations, urging 
appropriations. 
(h) Forecasts and Warnings for Stock Growers. — This service covers the western and 
northwestern portions of the country and consists of warnings of cold waves, high winds 
and heavy snows. These warnings enable stock men to make proper provision for 
the. protection of stock exposed on the ranges. They are of especial value to sheep 
men during the shearing and lambing periods as heavy losses sometimes occur when 
proper protection has not been provided, sometimes as much as 50 per cent of in- 
dividual flocks. In the States of Washington, Oregon, and Idaho alone there are two 
million sheep valued at $12,000,000, exposed to the weather and the sheep men depend 
largely on the Weather Bureau for information as to when protective measures should 
be taken. 
(i) Fruit Frost Warnings. — This service is maintained in a number of important 
fruit growing sections of the country, particularly in California and Oregon. A killing 
frost without warnings or protective measures means disaster to the crops. So im- 
portant has the work become that a trained meteorologist is assigned to important 
districts during the frost danger season to determine how low the temperature will 
fall and to advise as to the extent of the protective measures that must be taken. 
(j) Forecasts for Alfalfa Growers. — Special warnings are issued for alfalfa seed growers 
in the principal seed producing sections of the West, and for alfalfa hay making in 
nearly all sections from the Mississippi Valley westward. Frosts are frequent at 
about the time alfalfa seed is maturing and are very damaging to unharvested crops. 
It is estimated that near harvest time, the crop increases in value at the rate of about 
five dollars an acre during each twenty-four hours; if it is cut too early, much loss is 
sustained but a heavier loss may result from frost if not cut early enough. On the re- 
ceipt of a warning, the growers vigorously push harvesting operations to save as much 
seed as possible. 
In addition to the seed growing service, fair weather warnings are sent to all the prin- 
cipal alfalfa growing districts of the West, during the hay-harvesting period. In 
Oklahoma alone two thousand alfalfa growers receive these special forecasts which are 
distributed through the County Agents of the Farm Extension Service. 
(k) Fruit Spraying Forecasts. — A special fruit spraying service is maintained in 
New York and other important fruit growing districts, by which special forecasts are 
made for the benefit of fruit growers during the spraying season. The effectiveness 
of spraying depends largely upon the weather conditions at the time and immediately 
after spraying, and this service is of much value in supplying information as to the 
best time at which this work should be done. This service has been so successful that 
requests are on file for the establishment of similar work in a number of districts not 
now covered. 
2. Highway Weather Service; 
This service consists of the issue of bulletins, daily, semi-weekly, or weekly, depend- 
ing on locality, giving the conditions of the main highways in the section in which 
the distribution centre is located, and their passability as affected by rains, heavy 
snows and other conditions. Detours and other pertinent information are included. 
Bulletins are issued at about 50 stations in 30 states. These bulletins are used by 
travelers in determining journeys and routes, in the dispatching of truck, determining 
loads, etc. 
