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Hurricanes Robbed of Their Destructive Power
CITIKS along the Gulf of Mexico Coast of the I'nited States are resting easier, ship owner have lost bill their worries, marine insurance rates are dropping ind the families of ship officers and feilori are no longer the prey 01 the storm-fear, since the weather bureau of the United States Department of Agriculture ha- announced the discovery, by Dr. lilac M. Dine, forecaster at New Orleans, of a new and accurate method of foretelling the coming of these hurricanes, within in tO 12 hour- alter they enter the Golf of Mexico, and from 24 to 48 hours before they become dangerous to coastal cities or to shipping leav ing any of the ports. For twenty years, Dr. Cline. who has been sta tioned in the service of the weather bureau all along the gulf coast, from Key West on the east, to Galveston on the wrest, has been working- on his theory that the height of the tides along the gulf coast tell accurately of the approach of the hurricane long before even the sensitive barometer warns of the coming storm, and that these tides not only tattle on the hurricane, but that they tell its ! cation, direction, velocity, destructive abilitv, and appro: match where it will hit the shore. During those twenty years, from the beginning of 1900 to the end of 1919, despite the work of the barometer, of ireles warnings from ships, and the steady labor of observers all along the coast, hurri canes raging into the Gulf of Mexico from their VXph terious birthplace in the tropical Atlantic took 7.225 lives on the gulf coast of the United States, and in flicted property damage of $105,642,000. This is an average of rather more than 360 lives i . : r io i ns a year, ana property loss oi .-c-.iw ever) twelve months, though, as a matter of fact, all this destruction of life and property oc curs in the months of August, September and October. The storms arc annual events. Contrasted with this are the figures for the year 1920, the first hurricane season in which Dr. Cline's new method of warning by the height of the tides has been in effect. This year, though the hurricanes were se vere, and one of them in particular hit in shore shipping and the coast with terrific fury, only 18 lives were lost, two rather small vessels wrecked, and damage to ports and towns esti mated at less than $100,000. The answer to this great prob lem in subtrac tion, of course, is that the cities and towns and ports, the ship operators, the fishermen and the people generally had time, in the four days of warning given by Dr. Cline and the New Orleans branch of the weath- r bureau, to pre pare for the storm, to know just where, at what times, and with what force it would hit. Next year, the loss probably will be almost nothing, provided all ship owners heed the warnings, all the fleets of small boats lay in their berths and the towns prepare their wa ter front properties for the hurricane, which, according to Dr. Cline, is very punctual in keeping the dates the ris ing tides make for it. The secret of the discovery is merely this, in Dr. Cline's own words, as he told it to the correspondent of Thh Dkarborn iTDEPENDBNT. "With the approach of a hurricane to the gulf coast, the tides rise from the cen ter of the hurricane's path to the right of that path, and are lowest at the left of the course the storm is taking. Thus, if a hurricane be approaching the coast, between, i New Orleans I ut.d Mobile, and if the tide is notabh higher along the mouth of the Mississippi River, and notably lower on the Mobile coast, then the hurricane will strike closer to the mouth of the Mississippi, and New Orleans, than '"bile. This announcement would be known to the tidi observers from 24 to 48 hours before the 1 r gave warning of the coming storm." Q his own .statements from a recent United States Weather Bureau report entitled. "Relation of Changes in Storm Tides on the Coast of the Gulf of M CM to the Center and Movement of the Hurri canes," he says : "The waves and swells of greatest size and length are developed in the near right-hand quadrant of the cyclonic area, and move through the smaller waves in the front of the storm, and are carried by inertia to the shore in the direction in which the cyclonic area trancing at that time. The waves sent out in other directions, being smaller and shorter, do not persist long a iter leaving the cyclonic area and soon flatten out and disappear. The transference of water With the long waves and swells causes rises in the water along the coast, which increase as the storm ap proaches. The rise of water along the coast, in front of the line oi advance of the cyclonic area, beginning U to Z4 hours after the hurricane enters the gulf in dicates the rapid movement of the waves through' the storm area and across the gulf. By HARRY H. Dl NN "From study of the movement ihtwtf Oi the dit ferent charts and figures, collected by me during UK past twenty rears, this ipeed is shown to vary from So to 45 miles in hour The rapidit) with which tne waves travel depends both on the extent Of the O clonic area and the intensity of the winds that de velop the waves and swells. The water rises at the shore in the front and to the riht of the point toward which the center of the hurricane was mov ing at the time the waves started on their journey. "The rise at shore of the wa ter from the hurricane shows long in a dvance of any change in the barometer. Take, for ex ample, the hur ricane of Sep tember 11-14, 5 PlTB W-ymmMSS&H&& '-BkS&St fPff nniiif, .muff fflriijfflnirflll',L Top Dr. Isaac M. Cline, district forecaster, stationed at New Or leans, whose discoveries rob hurri canes of their terror; second A so called storm-wave; third Studying barometer at Shipping; Board's en gineers' school ; bottom Studying rescue of persons from storm stricken vessels. TMll I , I U ISs?s nft bb aat h sw amsvssm 1919: When the barometer at Burrwood. New Orleans. Ga vesten and Corpus Christi was either stationary oi falling onfr a few hundredths of an inch, the water. Arsni. :l'rrwood' !ater ,at Galveston, and then at 'th?m .' ! ri"lg b fet. tetlin the story of the movement and of the change in the course of the storm as plainly as it could be told without words fore aV.'.wV. mformatil'" " ' by the tid in forecasting the movements of hurricane, the tides si M S?KC0Mt l"d C" Sulhould i pwttedfor each hour . whenever storm appean on the gulf The height of the tide above mean owtidi should be telegraphed from coatt lUtEnTwhh u i,. , . , 1 mbn the water exceed rf.tt'of'A.d the fine watll :..;;,,; . "i at "The intensity ntiH s.- c rlirrtt, ,! .. i r v WHl ' w nurricatie are m- irriciiio -If ! . . ua ' 7 " c t.Mfiii oi me coast am u,Kiri, - - i iv 1 1 that rise is takinc aIm utll depend upon the ranicHt) with which the ardoi area is advancing and the intensity of the hurricane U the point oi greatest rrse in the tides shifts richt or left tins fth.f1 mdicatei that the storm i chansrinc its course in that direction toward which the S rise is taking plait. When the crest of tl storm tule is coincident with the crest of nt regular tide the height of the wafer will he greater by n than one fool for hurricanes oi equal intensity, tl when the Crest of the storm tide is coincident with 1 . tide and rn forecasting fttortn tides tins must be bo: in mind. The regular tides ire not obscured at time by the storm tides, except at or near the p. at whkh the storm moves, or will move, inland, I then for only about 1-' hours before the pass.t of the center of the hurricane. "The htghesl water occurs a few miles I the right, and about the time of the pataaj of the center of the cyclonic area. At points on the coast some miles to the right of t line of advance of the center of the stor the highest water occurs on a line drav. through the center of the cyclonic area right angles to the line of advance of t hurricane, about the time of the pasa. of the center of that storm across that In. The hieh water extends for only a sh distance to the left of the point where th center of the fttortn moves inland. Hiffl water, however, is experienced to the rii of the center for I distance varying from l1 to 200 miles "The water commences rising at the shore toward which tin cyclonk area is advancing lc-- than J4 hours after the center of that cyclonic area has entered the Gulf of Mexico. The waves and swelK which give this rise must have moved through and out of the rear right-hand quadrant of the storm are; within 12 to 15 hours after the center of the storm entered the Gulf of Mexico. This indicates that wit!; a 'fetch' of 150 to 2l) miles in the rear right-hand quadrant of the cyclonic area, the winds furnish sut nctent energy to develop waves and swells of a fttzc and length that travel 30 to 45 miles an hour, reach ing the middle gulf coast. 4oo miles distant, in 10 to 15 hours, and to reach the Texas coast. 800 miles di tant, in 15 to 20 hours. "Strong currents are created in the. right-hand sew ment of the cyclonic ana. which move, in the main, coastwise, toward the line along which the cycloni area is advancing. The tact that two gas and whistling buoys, in the storm of August, 1915, and three in that of September, 1919, were carried two to eight miles, nearly parallel to the coast, shows the force of these currents. If these buoys had been moved by waves, they would have been carried in toward the shore, ami not along the coast. The high water attending the hurricane is fre quently referred to as a 'tidal wave,' or a 'storm wae.' but it is not a wave in any sense of that word. It is a culmination of the water from successive 'storm waves' reaching shore, covering a period of two or more days, w ith a gradual rise which increases as the center of the storm approaches. "The 'storm tide' results from the physical forces of the hurricane, driving the large waves forward and transferring the water in the same direction as the line of advance of the hurricane. In the fjoen ftea this 'ste)rm tide' is not so great, probably not exceeding, in the greatest storm, more than five feet. The Obstruction formed b the ceast line acts u a barrier and th Water gradually banks up, as it do against a dam thrown across stream "The rise in the' water at shore fre quently is against opposing off-sho: winds, as uas the case in 1900 a 191 at (jalveston. Texas, and in 191 at Corpus Christi, Texas. In MM cases, the off-shore winds force th waters backward on the stream, retard mg the rise. Then, when thm shift and come in with the storm, th rise in water is much more rapid, and, coi equator, much more destructive. Th. Ai mmished pressure near the center of t! hurricane will have some effect on the hekl is about equal to that of one foot of water. Thus, t;r a" J ,hcr- of ter due to d m, Cakes?, oS7C at GaK,cs,on- ,d"riK the 1900 storm at net. r ' txuam',le' wh the barometer at 2M M ! was IS fS eXCeeded lJ (Mt yet ,he St"': With t! bia ability to foretell virtually all necess... n ' hi GuMtf!" ,Prohini hurricane, ihip K , 0 n the Gul of Ucxko can be warned of a storm I In .l V' "!"' ar" r"'l,i"-d to "oss the If o U "r'lN a, FMhip i-i the middle of the eiSier li? v2S '""niediatel, a hurricane anteri n i st us nl '''' hanuel or h'lorida Strait-the ta I c mi; t', "' f"r hese storms fi Of ffiM"' V"-'"' 1,1 ,hc topical KfkM to en ' , ; ,T :,'TUM tX'"w 1 'ther to proceed a hie , . r ' O l,,C A"a'"K ,hc " SwWgh a harb or f u "'" ,"",n",k'' "r Mk sachortge it returato , ,,r ' Mco, or even to border on th. v" n'm?,l? ?f lh nva Mates which shh L , k rn, ,U "rU1 Mlitemiiaa Similarly, t hw iul , T '" at a. flash from the wireless, at 1. ad Hu m fi?rr !",e Sea Ia" "f trade would r on wh en h, h"r(ric?'-'s Ue those ports I handn st r '' "' m"" woM not meet the siiiiiiiinir rnm nd out their fleets as usual ii "WCSLL'H! rSJ ,,r north or ,r and can so aher a"a' ,,k"w,se Mn warned, ran he un in rnn r CU"e5 s lo mi" the storm, or "c up ,n convenient ports until it has passed.