JULY 1935 MONTHLY WEATHER REVIEW RIVERS AND FLOODS [River and Flood Divlsion, MONTROSE W. HAYES, in charge] By RICHMOND T. ZOCH 231 The moat disastrous floods during July were those in New York and northeastern Pennsylvania. Record breaking stages were reached in practically all of the srllall atreams there, causing the loss of 52 lives (40 in New York, and 12 in Pennsylvania), and about $26,000,000 in property, $25,000,000 being in New York State. The following is an account of the meteorological con- ditions which caused the flood-producing rains, prepared by Charles L. Mitchell of the Weather Bureau in Wash- ington: The heavy rains were due, not to any single cause, but to a com- bination of causes. At 8 p. m. of July 3 a well-defined disturbsnce was moving eastward over the Hudson Bay reqion, and an ill- defined, slow-moving disturbnncc was over the Rocky Mountain region and the Plains States. A t t h e same time a maEs of polnr air had begun t o move southw:ird over northern Canada. During the next 24 hours the northern disturbance had nioved rapidly e%t- Southeastward t o the lower St. Lawrence Valley, the western dis- turbance had assumed more definite form and was central over South Dskota, and the polar continental air had overspread the Hudson Bay region. By the morning of the 5th the center of the northeastern disturbance was over the Gulf c,f Si. Lswreiice arid the Dakota disturbance was over Minnewtx and est1 cine western Ontario, moving northeastward. Howel er, its further :tdrnnce in t h a t direction was blocked by a wedge of the polar coittinent:~l air that hnd by this time pushed southeastward over James Bay and northern Ontario. With the center of the northern high pre56ure area still west of Hudson Bay, the disturbance was not nicrely blocked in its northeastward movement, but was carried nlonz tiy the general drift of the upper air tonnrd the east-southeast until the morning of the 7th, when the renter was near Buffalo, N. T. Meanwhile, the front of the pclnr ccrntinentnl air mass which had reached northern New England and extreme northern New York the evening of the 5th, pushed southward and southwestward, and at 8 p. ni. of the 7th this cold front extended from a short distance south of New Haven, Conn., northwestward t o Lake Oiitnrio, through or very close to the area over which excessive rain waq then falling and continued t o fnll through the night. For the second time the disturbance was blocked and it ninde no further eastward prog- ress; but its center drifted slowly southward during the nest 24 hours and merged with another disturbance that moved northeast- ward from Georgia t o the New Jersey coast where i t was centered the evening of the 8th. Due to this unusual metdorological situa- tion a mass of warm and very moist tropical maritime air moved north-northwestward over eastern and central New York, while at the same time a mass of polar continental air was moving south- eastward over the Lake region and its front had reached eastern Lake Erie by 8 p. m. of the 7th. The inevitable result was that for a period of many hours, by the physical processes of convergence and forced convection, the continuous stream of tropical maritime air was lifted rapidly; and heavy and prolonged rainfall occurred over a considerable area, of which Cortland appeared t o be the center. Wherever the tropical maritime air maaa was forced to rise over elevated areas the rainfall was naturally even heavier than over other sections where the wind was not upslope. The following comments of John C. Fisher, Weather Bureau Office, Ithaca, N. Y., are of interest: Thunderstorms were general over south-central New York during the period July 6-9, inclusive, with the heaviest precipita- tion recorded on the 7th and 8th. Over a n area extendin from northerrl Steqben County eastward t o northern Delaware 8ounty new records for 24-hour precipitation were established a all stations. The heaviest rainfall occurred over a still more lii ted area extending from Iieuka Lake t o central Chenango County, in estent approsimntely 100 miles from west to east and 15 to 20 miles from north to south, and covering the divide between Finger Lake drainage to the north and Susquehanna and Delaware drainage t o the south; here from 9 to over 10 inches fell during the %day period July 7-5 inclusive. The distribution of rninfnll was unusually uniform for thunder- storm precipitation, but nsturnlly there wns considerable variation in amount. Observations indicate that while n few sections escaped serious damage, in other districts the rainfnll was undoubtedly much heavier than recorded by any of the standard gages. The only automntic rain gage in the area of maximum rainfall is located at Ithnca; so this record, which shows the time of fall of each .01 inch, is of considerable interest. Previous rerords of severe thunderstorms show greater intensities of rainfall for periods of from 5 minutes to 2 hours; but the former %-hour maximum amount was 4.70 inches, while 7.90 wns recorded between 4 p. 111. of July 7 and 4 p. m. of July 8, 1935. If this record is indicative of conditions throughout thetrea, the rainfalls were not of the type coininonly characterized as cloudbursts”; in other words, while the amount of precinitation falling in 24 hours and 48 hours exceeded all previous records, the rate of fuZZ was not unusually high at any time. I n this portion of New Pork State the topography is rough, with many small streams discharging steeply into glacial valleys. The unprecedented rainfall brought many of these streams t o flood peaks so sudden and high that people were caught practically unaware, trapped in houses, automobiles, and cottages on the shores of the Finger Lakes. During the early hours of July 8, crceks whose sunimer flow is usually insignificant discharged water many feet deep through the centers Gf Prbana, Hammondsport, Watkins Glen, M ontour Falls, Myers, Truniansburg, Marathon, Lisle, Willett and other towns and villages. Trees, buildings, and other debris jamniecl bridges and culverts, streams were diverted, roads washed out, houses demolished, fields deeply gullied or buried under gravel, railroads washed out, and bridges cnrried away. The run-off t o the north submerged thousands of acres of highly productive muck and bottom lands, while the Canisteo River at Hornell and the Chenango at Binghamtoii flooded residential and business sections, as was also the case a t Ithaca, Bath, and many otlter towns in n lesser degree. Estimates of total damage vary, and some items can hardly be approximated; however, i t is considered that $25,000,000 is con- servative. The loss to State highma) s was approximately $3,- 000,000, of which $1,750,000 vias damage t,o bridges; damage to town and county roads was very probably greater, with some 540 bridges of a span greater than 5 feet to be replaced. The railroads, excluding loss of business, suffered property loss in excess of $1,250,000. Public utilities had heavy damage, as did the State parks at Watkins Glen, Enfielcl, and Taughannock Falls. Damage to urban property was in the millions, but no accurate figures are available. Suburban damage, including buildings, livestock, destruction of crops, loss of use of land, soil erosion, etc., was probably greater than any of the above items. While the loss of 40 lives was directly attributable t o the floods, prompt action of the proper authorities provided food and shelter for those driven from their homes, and also prevented any out- breaks of water-borne diseases. All streams in the Mississip i System passed below flood stage during July. All o f the important features of these floods have been mentioned in previous issues of the MONTHLY WEATHER REYISW, There was also great damage through inundation. 232 10 10 11 9 MONTHLY WEATHER REVIEW JULY 1935 Fed fi.8 13.0 15.8 20.1 Table of jlood stages in J u l y 1935 1.411 dates are in July unless otherwise specifled] 8 8 9 10 7 7 Table of jlood stages in J u l y 1935-Continued [All dates are in July unlcss otherwlse specifled] 13.0 14.4 14.4 12.1 22.0 27.7 4 b O ~ flood stages- dates 3 4 3 6 6 5 25 crest 24.4 23.6 21.0 20.0 27.2 11.5 18.8 i bove flood stages- Crest dates Average preswre ~~ Flood stage Depur. ture Eiver and station Inehra 29.69 29.55 ?9.91 30.li 30.06 30.09 30.34 29.86 30.04 30.00 30.03 30. l i 30.05 30.01 29.95 - TO- Inch -0.25 +. 11 +.19 +.04 +.01 +.07 -.01 f.09 +.02 +.02 -.01 -.02 -.02 -.02 __.-_.. Flood stage River oud station - Stage Frcm- Date From- 10 10 9 8 8 8 9 9 10 16 22 6 7 1 2 1 1 3 4 2 6 4 5 25 Date 10 10 10 8 8 8 9 9 10 17 26,27 7 6 8 4 2 7.8 3 4 3 6 6 5 25 Arkansas Basin Arkansas: Fnrt Lyon, Colo _._.._._________... Van Buren, Ark .____ __________ ~ __. Red Baain Grand Ecore, La.-. __. __ ___ .~ ___ Alexandria, La. .___ __ .. __. - .. .___ __ Red: ATLANTIC SLOPE DRAINAGE 1 Fcpf E Lackawaaen: Hawley. Pa.- ___.. .______ Lehigh: Lshighton, kd .________...___.. Schuvlkill: Reading, Pa ...._.__...___.. Cheniuna: Corninc. N. 1- ______________I Feet 5 22 33 32 43 46 46 35 28 22 17 41 3i 22 25 15 ~ Feet 6.9 22.5 35.7 41.3 44.7 48.0 38.4 30.0 23.6 17.4 49. a 42.5 39.6 24.7 25.9 18.6 - 22 3 May 20 May 8 June 8 June 1 May 31 May 30 June 5 June 8 I June 4 May 20 Mar. 15 3 29 - 22 2 4 11 12 17 19 20 19 17 13 16 20 28 12 (*) __ 22 2 1 June 4 4.6 4-7 4-10 5-11 6-11 9-11 8,9 b10 4-11 11-15 9 30 9 16 7 11 14 12 16 22 12 14 12 14 13 21 27 12 20 26 24 21 11 17 Susquehinna: -' Oneonta, N. Y .....__...._____-____ Buinbridge, N. Y ____._....________ Binghamtnn, N. Y .______._________ Towanda, Pa _.._..___________.._.-- Wilkes-Barre, Pa ..__________. ...___ Tar: Greenville, N. C ___________...____ Savannah: Ellenton, 6. C-- ____________ MIssissirrI SYUTEY Upptr Miuuisaippi Basin Mississippi: Krosuk. Iowa.. . - . - --.- - -- ----- ---- Quincy, Ill ...._.___.____.__..______ Hannihal, Mo.. . . . .- _____________ __ Louisiana, Ma. . . . .___ .____ _._ ..___ Alton. Ill .... . . . . . .._.__.__ ~ .. ______ Chester, ill^.. . .. . .... _.___. ... ____. Niraoriri Basin Solomon: Niles, I;.?LIs.. - .-. ..- ..._.___. Smoky Hill: Lindsborg, Kans.. - - ________ _____ __ Selins, Kans.. . -. ____________ _.____ Ent.erprise, Knns ._____. ___._____ ___ Ohio I h i n Tuscaraaas: Coshocton, Ohio ____ ______ Little Miami: Kings hlills, Ohio _______ 11 10 10 10 11 17 27 16.7 18.5 17. 7 Loiocr Nississippi Raain Mississippi: Vicksbure. Miss .___.....__ _.__..___ _I Natchez, Miss ____ . . .______._____ _.. Angola, La _.________._ ____________ Baton Rouge, La Donaldsonville, La _____ ._ _..__._... I Reserve, Lo ____..__.._ _____._______ New Orleans, La ____.._..____._..._ Atchalalaga Basin Atehnfalava: Bimmisport. La.. . . .- __ __ -. .-... .-. hlelrille, La _..._ ___._ ____ .____ __.. A tchafalaya, La.. . . - -. . -. -. -. . - .. . . WEST GULP OF MEXICO DRAINAGE Trinity: Liberty, Tex _______ ___.__._ __ __ Niieces. Cotulln, Te\- _____.._.__________ Flood continued into Augul;t. WEATHER OF THE ATLANTIC AND PACIFIC OCEANS [Tho Marine Division. W. F. MCDONALD, in Charge] TABLE I.-Aaerngea, depariim?s, aiid extremes of atmospheric pres- a w e (sea level) nt selected stations f o r the North Atlantic Ocean and