MOKTHLY WEATHER ~~~1~727 107 THEHURRICANE SEASON OF 1961 GORDON E. DUNN and STAFF U.S. Weather Bureau Offlce, Miami, Fla. 1. GENERALSUMMARY TexasTowers off t'he Sew Englandcoast. Ships also reported BS-kt,. windsin Inga on oneor two occasions. While the number of tropical CJ-C~OI~CSwas exact'ly the annual average for the ltrst t,Elree clecades, the llurricwle Previously in only eight,years since 1900 had there been as season of 1961 wasremttrkublc for tmhclack of activity tnany 11s eight8hurricanes in the Atlant,ic area [I]. Only one t,ropictllcyclone developedprior t'o September. June through August ttnd the verv high cyclone frequerrcy of Septembert.hrough Novenlber, tdso for t'lw large Activity in the tropical Atlantic in August' was at a min- number of storms of fullhurrictme i~ltensitmy-- -eight. irnnrn ant1 this was the t.hirdconsecut,ive August with Indeed, tthe number could well be ninc, or cvcn ten, since subnormaltropical cyclone frequency. Hurricanes oc- Gerda, during a period when it,was stmillregt~rded tis partly curred over nll portions of the Atlantic and there was 110 tropical, was at8t8crldetlby hurricanc.-for.ce windsat. t.hc concerltrated area of activity (fig. 1). NORTH ATLANTIC TROPICAL CYCLONES 1961 DATE JULY 20.1, SEPT. 2-11 SEPT. 3-15 SEPT. ,-,(I SEPT. LL-1II FIGURE1.-North Atlantic tropical cyclones of 1961. Unauthenticated | Downloaded 10/06/21 08:18 PM UTC 108 MONTHLY WEATHER REVIEW MARCH 1962 FIGURE2.-Surf:~ce weather chart,, 1800 GMT, September 11, 1961, with four fully-developed hurricanes in evidence. Unauthenticated | Downloaded 10/06/21 08:18 PM UTC MARCH 1962 MOKTHLY WEATHER REVIEW 109 FIGIIRE 4.-IIImicane Anna at 1048 EST, July 21, at approxim-ately 14.1' X., 52.4" W. Tht: northern coast of South America and the Gulf of JIaricaiboand Isthrnus of Panama can be seen south :md southwst of the cloud mass. According to Tistltdc [Z], there \vas a pronoultcctl sllow~lsouth of the st20rrn trntl Ptmanla and CostmaRica reversal in t8hegelneral circulat~ionfro111 August, to Scp- can bc: seen at thc lowerleft of the picturesomewhat ternber wit8hthe slrorlg ridge over westcrn h-orth America tlistort'cd by the angle. The classical spiral band structure being replaced by tt dccp trough. Conco~t~it:mt~wit,ll this of t~ hurricane is shown in Betsy on September 8 shortly trough development,strong :tnt~icyclogcl~esis took pl;~ce after it began a sharp turn to the northeast (fig. 5). A over eastern Sort'h America with t~ positive height. (lepur- TIROSpicture of unusuallylarge hurricane Carla is ture of 180feet' at 700 nlb. over Afaine. The p:ittcrn of shown in figure 6. The centerposition of t,hehurricane the height. tlnornal3- over the Atlant'ic at t,his level rescln- W:IS irtdicrkted by the satellite us near 26' N., 95' W. The bled the circul:ltmiorlfeat,ures found by Rdlertzw-cig [3] ac.l11:11 centerposition was tbpproxirnatcly 27' N. Hurri- to be favorablefor tropical cyclonc tlcvelopltlent in tmlw c:m(' Debbie on September 10 is shown in figure 7. This eastern Atl:mt,ic, andfour 1lurric:irtcs in sucwssion stor111was first,picked up int'he Cape Verde Islands. Since developcd in this nrcn during t'he first ldf of t'he ~llontll. it, could not be reached by reconnaisstmce planes, its move- On September 11 thew four were siltlulttllteollsl3- of full ment, was forecaston the bmis of climatology. The hurricane irlt8rrlsit8yin t8he Atlant'ic R~C:L(fig. 2), the first sut,ellit8epicture on the lOt,h indicated that there had been time thisis known tollavc occurred. D:mt:tgc :~nd :L rnuchlarger northward component of motionthan fatality statistics arc shown in table I. indicated by cdirnat'ology. The existence of Esther was Some of theweather satellite poterrt'ial inhurricane not confirrncd by rcconnaissmceuntil September 12. detection andt'racking was delnonstrnted in 1961. The However, as early :IS 1412 EST, September 10, TIROS I11 track of Anna (fig. 1) was begun at 60' W. late on July 19. st,ronglyindicated the existence of a tropical cyclone (fig. 8). Intleed, it seems likelyfrom the photograph it However, TIROS I11 at, 0940 EST, July 17, :kt about812O may have been of full hurricane int,ensity at this time. N., 43' W. showed that at' least a dcpressiorl was prcseltt It does not appear t#hatit' will be difficult to differentiate (fig. 3). The line ext8erdirlgeastward from the cloud Inass between the cloud masses associatedwith upper tropo- is probablyt'lle Intertropical Convergcrlce Zone (ITC). sphere vort'ices and tmhose accompanying tropicalcyclones. (All thesesatellite pictures are print'ed so t'ht Iligher Thus, the sat,ellite without doubt is already an excellent latitudes are toward the top of the picture.)Hurricanc detection tool. The cent,er can usually be located within Anna four days lstcr is shown in figure 4. Tlw northern fZO. The more sophisticated weat'her satellites planned coast of Sout,hAmerica and the Gulf of Maricaibo are should reduce the average error considerably. Unauthenticated | Downloaded 10/06/21 08:18 PM UTC 110 MONTHLY TVEATHER REVIEW MARCH1962 evening of July 19. An area of suspicion was first noted w-ell to tlleeast on July 17 as Navyreconnaissance reported an extensive area of strong radar echoes between 14'-16' N. and 50'-55' W. Shippingin the area also report'ednumerous showers wit,ll windsgenerally light and variable. TIROS showed the principal concentration of weather near 12' N., 43' W. (fig. 3). During the 18th and 19th the ITCshift'ed well nort'h of its normal position tlrd cyclogenesisprobably occurred at, its intersect,ion with the e:tst'erly wavefirst noted by Navy aircraft on the 17th. Following report,s from the islandof Grenada, indicating heavy squalls with gusts to 50 m.p.h. and pressure of 1002 I&. around midnight local time on the 19t8h, reconnais- snnce aircraft locat'ed Anna in the extreme sout,heastern Caribbean some 75 miles north of the Venezuelan coast on the morning of July 20. By wft'ernoon windshad increased to slightly over hurricane force. From its inception, Anna maintained a course slightly north of due west on its entire track through the Caribbean Yea wit'h R forward speed bet'ween 15 and 23 1n.p.h. and FIGUREB.-Hurricane Betsy as seen by TIROS I11 at 1515 EST, with lowest pressure 976 nib. (28.62 inches) on t'he 22d. September 8, 1961, showing classical spiralstructurc. The cen-. OJI the 23tl the center skirted t,he ext'rerrle northeastern ter is at about 36' X., 59" W., or 900 rnilcs cast of Virginia. coast of Honduras, then passed westward into t'he moun- tains of southern Brit'ish Honduras t'he next morning. Since Anna's track WLLS at an unusually low latit'ude, upper-airdata were sparse. Only when the, center was near a reporting station would t'he lower windsbe affected, but the available500-mb. data gave little indicationof a hur- ricane. However, at 200 rnb. a well-developed anticyclone was centeredto the northeast of Annaand maintained this same relative position as the storm moved through theCaribbean. Operat'ing as an efficient outflowmech- anism, this anticyclone played an important part in Anna's developmentand maintenance. This relationship of the two dependent systems could occur only ina deep easterly circulation such as existed over the Caribbean during this period, and may explain why thc size and int'erlsity of Anna remained so stat'ic. Some minor damage occurred at Trinidad and Grenada, but t'here were no casualties.Considerable damage was report,etl along tlle extreme northern Honduras coast with several hundred houses damaged or dest'royed, and many pltintationssuffered heavy damage to fruit' trees. One death and a dozeninjuries were reported from Trujillo and Bk~yJsltLds. More than 5,000coconut trees were blowndown on Utila, a smallisland off theHonduras coastdirectly in the path of Anna. No official reports FIGURE6.-Hurricane Carla, a very largestorm, 1730 EST, Sep- havebeen received from British Honduras, although tember 10, 1961 at approximat,ely 26' N., 95' W. unofficial information indicated damage was rather exten- sive at' Punta Gorda in tlle extreme southeast.The center of Anna moved inland over a sparsely settled area. 2. INDIVIDUAL TROPICALCYCLONES Hurricane Betsy, September 2-1i.-Theformation of l~urricane Betsy inaugurated ofone the most active tropical Hurricane Anna, July 19-24.-Anna, the first tropical cyclone periods inthe historyof the North AtlanticOcean. cyclone of the 1961 Atlantic hurricane season, developed No less than three other hurricanes made their appearance ashort distance east of theWindward Islands on the beforeBetsy dissipated. Betsy formed in the eastern Unauthenticated | Downloaded 10/06/21 08:18 PM UTC Unauthenticated | Downloaded 10/06/21 08:18 PM UTC 112 MONTHLY WEATHER REVIEW MARCH 1962 lolor , I I , I I , I I ' I ' I ' I ' centralpressure (931 mb.) on the afternoon of t'he 11th. Upper-air clata at the 200-mb. level vividly illustrate the 1000 - deepening it's during Carla fromtroposphereoutflow- upper stage (fg. 10). - 990 - The center of Curla was under surveillance for SOI~~48 *s by three land-based radars located at Brownsville, 980 - Gttlveston, arid Lake C'harles.showed All radars a - n strong cycloidal track during the period preceding landfall E 970 - 3 v1 le New Orleans hurricane center described Carla as Y 960 - - oneintense of the most ltwgest, ttnd destruct'ivehurricanes ever tostrike the United States Gulf coast.Carla's 950 - O'Connor-PortLavaca Port- cent,er the moved over inlund area on the central Texas coast during the afternoon of Legend US Navy 940- 0 - Scptetnber 11 (fig.