564 
GEOPHYSICS: C. F. MARVIN 
Proc. N. a. S. 
phoned and telegraphed to practically all maritime interests and broadcasted by wire- 
less to ships in the threatened regions. So nearly perfect has this service become that 
scarcely a storm of marked danger has occurred for years of which ample warnings have 
not been issued from 12 to 24 hours in advance. 
The sailings of the immense number of vessels engaged in our ocean and lake traffic 
are largely determined by them. Warnings displayed for a single hurricane are known 
to have detained in port on our Atlantic coast vessels valued, including their cargoes, 
at over $30,000,000. Fewer dangerous storms than usual occurred during 1919. How- 
ever, one unusually severe one occurred on the Lakes in November, accompanied by 
wind velocities of over 80 miles an hour. Owing to the ample advance warnings not 
a single marine casualty was reported. Only one tropical hurricane occurred, namely, 
that of September 6-14, 1919, that passed over southern Florida, traversed the Gulf of 
Mexico and struck the coast of Texas near Corpus Christi. It was attended by large 
losses in life and property that were inevitable, but the saving to ships and other 
property as well as lives was incalculable because of the warnings that were distributed 
well in advance of the storm. This hurricane was of extraordinary intensity and the 
efficiency of the warnings was so complete that the portion of the Gulf of Mexico which 
it traversed was practically cleared of shipping; otherwise many ships valued at 
millions of dollars would have been caught in the storm. Few, if any, ships caught 
within the storm centre could have survived. This efficiency of service added to the 
difficulties of the forecaster, because he was unable to secure wireless reports from the 
region of the storm centre which were so necessary for an accurate determination of 
the hurricane's direction and progress. 
(e) Cold Wave Warnings. — These are warnings of sudden and destructive tempera- 
ture changes that frequently sweep across the country during the winter season. They 
are issued from 24 to 36 hours in advance and are disseminated throughout the threatened 
regions by means of flag displays, by telegraph, telephone and mail. 
The uses made of these warnings are manifold. They are especially valuable to 
railroads in the making up of trains and the maintenance of schedules, to shippers of 
perishable goods, cattle growers, and innumerable business organizations. The warn- 
ings issued in a previous year for a single cold wave of exceptional severity and extent 
resulted, according to reliable reports, in a saving of over three and a half million dollars. 
No unusually severe cold waves occurred during 1919, although warnings were issued 
on about 30 different occasions for moderate cold waves. 
(/) Frost Warnings for Truckers, Tobacco, Cranberry and Sugar Growers.— Th^SQ 
warnings are issued whenever conditions indicate the occurrence of damaging frosts. 
The growers take advantage of these warnings to protect their crops by the various 
means in vogue. In many instances the growers are dependent upon the Weather 
Bureau for these warnings as without them their industries would be too hazardous 
to be profitable. This is especially true of early trucking in the South Atlantic and 
Gulf States. During the year 1919 rather fewer instances than usual of weather con- 
ditions necessitating these warnings occurred; but during the year previous it is of 
record that warnings of a damaging freeze saved nearly one-third of the entire sugar 
crop in Texas and Louisiana by enabling the growers to windrow the standing cane. 
Special frost warnings are sent to all parts of the tobacco-growing section in Wis- 
consin and Connecticut. Information of current weather conditions during the grow- 
ing season is also supplied to the other large producing areas. 
Frost warnings are sent to the principal cranberry-growing sections of the country, 
which enable growers to protect their crops by flooding or other protective means. 
They are indispensable to this industry. 
{g) Fire Weather Warnings. — These warnings are issued whenever conditions are 
favorable for hot, dry winds, which are favorable to the inception and spread of fires 
