446 MONTHLY WATHER REVIEW. SEPTEMBER, 1915
SECTION 11.-GENERAL METEOROLOGY
A REMARKABLE FALL OF HAIL IN MARYLAND.
By OLIVER L. FASSIG, Professor of Meteorology.
[Dated: Weather Bureau, Baltimore. Md., Sept. 4,1915.1
First accounts of hailstonos of unusual size are apt to be exaggerated. When the daily pa ers published reports
in the afternoon of June 23, 1915, accompaniod by hail as lar e as a baseball or an oran e, the writer was inclined to
ment literally, although soiiie of the accounts were accompanied by nieasurenients and detailed descriptions. Brief inquiry among the residents of Annapolis, where tho largost stones ap ear to have fallen, showed however, not only unusu3 accuracy in the first reports, but revealed the romarkable fact that tho first newspaper reports actunlly failed to give a sufficiently vivid account
of this phenomenal storm. Path of stown.-The fall of hail was apparently con- fined to central and northern Mawland and to Delaware, although thunderstorms prevailed over a niuch greater area, ostending into neiglihoiin States on the north.
in tho western portion of Carroll County, Md., and that the storm iiioved southeastward across Howard and Anne
of a severe local storm which passe cp over central Maryland
ma % -e further investigation %efore accepting tho state-
Reports indicate that the ha 5 began about 1:30 p. m.
Arundel Counties, crosacd Chesapeake Bay into Talbot, Dorchester, and Wiconiico Counties. It probably passed over the Atlantic, through Worcester County, at about
5 p. 111. Tho httil was particu1:irly destructive to cro s and esposed windows within the mrrow bolt, probab P y less than 5 milcs wide, estending from Union Bridge along the southwest border of C!arroll County, through Sykesville, Woodstock, Ellico t t City, Annspolis, Chi- borne, ancl Osford. (Soe fig. 1.) Juclging from tho size of the hadstones alone, the storm seeins t'o have attained its masiniuni intensity betivoen 2:30 p. PI. ancl 3 p. in., as i t passed over the city of Annapolis, althouc.li t.he stones were dniost m large, apparently, near $oodutock and Ellicott City, in Howard County, and at Clnibornc, across the Bay from Annapolis, in Talbot County. Othw storms qf t7ie dccy.--IInil, nlthou h not of unusual size, WRS re ortetl from a nunibor of loca?ities to the north
naniely, Darlington in Hurford County, and SudbmviUe in Queen Aiine's C'ounty, Md., and Millsboro in Sussex County, Dol. These towns are located along a line par- allel with tsho path described and tho stornis probably belong to another series, as they occured about an hour later m the afternoon.
of tho pnti F followed by the stomi described above,
Flo. 1.-The path of the hailstorm of June 22 1915, arross Maryland and Delaware. A, localitles reporting hall; fi, locallties reiortiug thunderstorms.
M . W. R., September, 1915. '0 face page 446.
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FIG. 2.-Hailstones gathered at the experiment station of the U 9 Naval Academy Annapolis Md June 22 1915
WM-glass fragments, +, inoh thih, from the shattered skylights of the Academy buildings.
(Bottom of tray conk hailstonas is lOh inches long.) Average dimensions of l0'seiected stonas wer; 34 by 3 in;hea;'kaximu& diameter of the largest meas% stone was 3+$ inchas.
SEPTEMBER, 1915. MONTHLI: WEATHER REVIEW. 447
Size qf ha.iktones.-The hailstones were of a size never before seen in this vicinity. The lar e ones were gener- ally referred to as being the size o 7 a ba3eball or an orange. Numerous niensurenients of indiridud hail- stonns were reported. Among the most reliable known to the writer are those innde by two officials of the United States Nand Acticlenip. Ten or twclve stones, accurately measured, gave an average diairietor of 33 x 3
inches, with a ~iasiiiiuin major dittiiieter of 343 inclies. In another series of nieasuremonta the largest stones exceeded 4 inches in dinmotor. Theso iiietwurenients are equivalent to a circunlforence ranging from 10 to 12
inchos. Roports from observers in other localities are in harmony wit81i tliese figures. A hnibtone piclid up at Ellicott City riieasured 9$ inchos in circuniference. Stones tho size of a baseball (i. e., 9 in. or 238.1; nini. in circumference) were not n t all uncommon don the path of the storm from Woodstock to Qaiborne. Afi accounts of observers at Annapolis agreo that the ground there was
never coverod with hail, and that the larger stones wore
probably never more numerous than 8 or 10 to the square yard (O‘Y4 sq. ni.).
individual stones are less nunierous.
llhiqht of haibston,cs.-St,atistics as to the weight of Infomiation uvail- ablo is to the effect that “thog averaged from 3 to 4
ounces”; thab “they ran about 5 to the pound”; that. “3
of them weighed a pound”; and I‘ that some weighed 6
to 7 ounces, while stones 4 to the pound wore not uncoin- mon ”. The circumference of a loa ue baseball pieasurns
9 inc.lies, and its wei lit is 5 ounces;%ence tho c..oniparison commonly made ho K (1s both as to weight n.nd size. StructairrP a.nd &a. )e.-Tho strwture of the hail was sipiilar to that usuhy met with, nmiely, R nucleus of snow or opsque ico, with concnntric shells of dtornatoly transparent and o aque ice. In some of the largor stones from 20 to 35 suc r i lagers were counted. Thero was dso the usual diversity in she e. Soino stones were nearly s herical; some spheroid$ prolate, and ohlate; some did-shaped; some top-sha ed. Sonie resembled a small cyniling,l some yere wit R prongs or knobs, and some without. Da,ma;qe don.s.-It is rather remarkable that such a shower of stones lasting from 15 to 20 minutes and pass- ing over a city with a po ulation of approximately
10,000 should have caused so Tittle personal mjury. The writ.er heard of only two mon who received scalp wounds of sufficient severity to require hospital treatment. Injuries to horses were numerous. According to reporb, one horse had the good jud,pent to take refuge in a neu-by grocery store. The force of the inipact of hailstones moly be gaged uite accurately from the clestruction wrought in the g 7 ass roofs of the Naval Academy buildinw. About half of the panes of glass in the skylight of %e gyninasium, between 400 and 500 in number, had to be replaced; tho glass was fully half an inch (1 cm.) in thickness. The skylights in the roof of the main building of the esperi- ment station, across the Severn, contained glass -fg inch thick with embedded wire netting. The acconipanging hotograph, figure 2, shows a tray filled with some of the farger hailstones atliered near the esperiment station.
the wire-glass shattered by the hail. The irregular and To the right and f eft of the tray are shown fragments of
____
1 Cymling. the sclll:pcd “pattypm” or slimmer squash ( Cucurbilnppo, Far. rondt nsr.4 Jso spelled “simlln. The Crntrirv Dictionnry saw “ SlmmI. . . . 2. A variety or quash hnying B round Rnttish head .‘.ith a iv%vvy or knlbpCil edge and so reemliluig tho cake [or simnel]: now ralled slmlin.”
spiked outline of.some of the stones is clearly indicated in the picture. The following interesting accounts of the storm and of the remarkable hailstones, are taken from letters received from Rev. J. k’. Dawson, S. J., of Woodstock College, a cooperative observer of the Weather Bureau, and from hlr. F. S. Bullard, of Annapolis, who is con- nected with the esperinient station of the Naval Academy:
The hailst.orm of June Z9 1915, wenie,l to ilevelop a few miles north or nurthwest of Rykcwille: s m w plsce between Sykes\-ille and West- minster. I t was wry videat near Eldersburq. on the Liherty Road, and (.in two farms in that neighhrhood pr&tirally the whole cro was dest.riiyed. The stones i n that rerion were smaller th:i.n at Wtmf stwk ani.1 ciit the corn to pieces. With 11s the dsrnsge was dune by breaking off the slllaller killi is. The stiirni nitived toward the south- wst. the center crush: t.he Rnltiniore tk Ohio I:ailmad near Gorsnch etation. :h u i i t 3 miles east of Pykesville. Thn eentrr pasRed a 1itt.le tv the west an41 swith of 118. and along tho 1inc of its pseagt? the stones seemed to be snisller than a t t!ie ctillt;,rre. I am indined to think that it went a little suuth oE Ellicott, Cit.y and north of Laurel, but am not siire. 1l‘it.h 11s the st.ones were not spherical. hut nere elliysoids, nearly all prdate. but quite a n i i d i r r ohlate. The Inwer iyere compcsed of f i i I I v -00 or 25 layers. a~teniate~y clear i r e sni~’~v;hit.e snrm ice. Cien- erixlly the nuc-lens \n.q riimpiised of white @lJfkr ice. I xiever saw any that c q d d blieni in size. The ni~nsnrt~ment~s I sent you (23 inchrsl n-ere not thuJse of the very 1srKeut. hiit were taken from stanes that were numerous.---J. P. Dairso)t, 8. I., TVuodsiocl: G‘ollt-p.
The hailetone pic.t,ure I sent voii was t,akm tv Mrs. Bullard. She rreighecl seven1 t i € them nnd the? ran atmiit. five tiithe poiind. I was st the experiment etation [of t.hc Naval Academy]. The hail- stones xere niiirh Inrger. ani1 there were more of them, on that side of t,he [Pcvrrn] river. I meizsored several that were over 4 inches in cliamekr. A very interitsting fraturc was their peculisr shape, being corered all w e r wit,h nohe or horns: others W C ~A pear-shaped, while d i l l others \wre wedge-shaped. with rounded top. Some of the larger oncq had snow inside. A few r;f the lnrcer Htiines crashed t,lirwigh our skylight like a cannon hall and fell to t.he flmr unbroken. The eninller ones just. shattered the glass. which wae pS inch i n [thickness] and reinforced with wire. The storm lasted from 15 to 20 minutes. The spec-tacla on the wat.cr was very weird and interesting. The crplmhes of the falling hail- stones rwe 3 or 4 feet. and there were eo many of them that i t looked as
if the river rose right up. The hail waa so bhick that you could not
see across the river. I inclme a small piece of the broken skvlight. The damage at the esperiment station u-as ahnut $3,500.-F. S . Bulbrd, U. S . Naval
deadmy E.rpsrinwnt Btation. Annapolis, Nd.
An interesting but unconfirmcd account stated that sninll ehbles were found at the center of some of the larger R nil gat.hered at Annapolis. The young man who relilted the story offered to produce the pebbles, but has not yet done SO.^ The observer was doubtless sincere in his belief that the pebbles were in the hail as it fell, but as tho hailstones in question were ap iarently gatliered
up w1ie.n the hail struck the ground, and t.hat t,he were
melted. h t i l a more accurate account is at hand of t,he circunistmcw ‘under which the hail was gathered and nielted, the story must be olassed with the nunierous runiors which may be labeled “important-if true.” Pwvious a.ccoitn.ts.-The literature of hitilstornis con- tains relerences to stones of larger size t,lirtn those gatliered at Annapolis on June E, 1915, but such instances are
r:we nnd, so far as the writer is aware, confiaxl to foreign lands. Dr. von Hann, in the latest edition of his “Hand- bucli der Meteorologie,” cites occurrences of hailstones measuring from 4 to 6 inches in dinnictcr and weig1ii;ng over a pound. M7e frequently read ahout l i d 01 iiiuch greatw size, but such rcports, upon inve~tigntiou, gen- erally prove t.0 be esaggerations; somctiines they refer
in the street, it is probable that the pe lh bles were picked
too deeply embedded to be noticed until t,he hai P stones
*Since writing this the author states he bxi received some of these pebbles.
448 MONTHLY WEATHER REVIEW. SEPTEMBER, 1915
to a cluster of individual stones which froze together while falling or after reachinn t,lit? grouiid. India seems to be a land 07 frequent occurrence of Iwil of unusual size. Eliot, in a study of Indian hailstorms, tabulated nieasurenieiits of the hailstones of GOO stoi nis, and found thnt in 27 per cent of the metisureimiits the stones wexe sninller than pe:i.s; in 51 p ~r cent they were larger than p e ~, but smaller than a, lemon; in 22 per cent they were lairqer than a lemon. Anot.her invest% ator, Rruist, found the w c m wra.riiln.uwz c.irctm$itwice of
fndittn hnilstonc~s tlo be from 4 to 6 inches, with a weight varying froni 2.2 t.0 4.4 ounces. The largest werc 10 t.0
13 inches in circuinference, weighbig from 0.62 to 1.24
In t?ne light of recent. knowledge of t,he temperature conditions esist,ing in the upper atmosphere and of the eneral weather conditions which aoconipany severe loc>l %sturbances, such as t.ornrtdoes, thunderstorms, and hail- storms, it is not .z dificult matter to account for the pro-
duction of hail during, t,he warm months of the year. But the ninnner in wliicli masses of ice are sust’nined in the at.mosphere long enough to acquire n weight of ninny ounces is st.ill sonietliing of it mystery. I-lowercr, we
pounds.
--
FIG. 3.-G13ieral weather conditions at R a. m..,June 22, 1915. The hailstorm occurred sir hours later along the dotted Ime, H, arross Maryland.
know t,hat hailstornis esliihit evidences of rapid and powei4ul rising currents within the central cloud inasses ;
thnt there is generally an incessant play of li htning
grcnt heights, retaining the liquid character of t.heir par- ticles in a subcooled condition with temperatures far be- low freezing. Volta long ago accounted for t,he onion- like structure of hailstones by assuming that the hail nucleus, once forined, is kept in a state of oscillation he- tween opposit.ely electrified cloucls until the constan t accretion of lavers of ice so increttses the weight that the
hailstone can be no longer sustained by the movements of t.lie atmosphere, and falls to t,he ground. Varintioiis
in the electrical potmt,ird of cloud particles are known to cause the part,icles to coalesce. Perrcl suggested that t91ie
strong ascmsionnl currents w i t h a hails t.orni cnrried the hnilst.oiies to great heights, receiving constant accretions on tlipir way, ~i i d that it is proba1)lc that the hail, falling out, of the atrong ~~scensioni~l currents or bring thrown out, niay he rcpentctdly citrriecl iip to dl;ltitutleu where the teni erature is bcl.ow freezing nnd thus grow to great
Genera.2 weather conditlolrs.--‘rhe 8 a. ni. weather niap of June 22, 1915, showed it general condition very favor-
between t.he cloucls, ttncl that these clouds are bui f up to
size % efore falling t.o the .ground.
able for the formation of severe local storms. (See fig. 3).
A well-developed and extensive area of high mssiire was iiioviiig rapidly enstwart1 Itcross the Centra t States. There w:ts tt 11ltiTo\v ridge ot rclittirely high pressure over the New England Sirttes and esteiidinq southward over thc Atlant8ic Occaii. The Lower Lake Region, the Middle and the Soutli A4tlimtio Stmutes, were in ti trough of low pressure. wit,li u sli:trply defincd “ squnll line” sqmrating the sontherly and ea8 tcrly winds nncl overivts t skies
froin the strong westerly winds ;mcl clear skies. The V-shaped dopression mas nioviiig f roin southmest to
northeast, across the l\riitld!e ALlnntic States ; the local thundeist~orms m t l hni Istornis which formed dong the silnmcing front of thp iircii of high ~rcssure, or alona the squall line, niovc(1 soutlieastward itcross MltrylanJ and Deltiware at the rate of approsiiiiatdy 50 iiiilcs pcr hour. At Bdtimore tho barometer fell steadily from niid- night of June 31 to nearly 5 p. 111. of the E d , when it
rose ahruptlg 0.05 iiich. This jump mtts accompanied by a change in the direction of the wind froni southerly to northerly, riiiirking the passing of the “squall line.” Earlier on t h 22~1, between 1 :30 p. in. and 3 p. ni.! 8
thundwstorm ww observed west of t,he city nioving from northwest to southeast. ZTncloubtedly this was the storm which >roducecl the heavy fall of hail nt intervals along the pat I froin Cnrroll Couiity to the Atlantic Ocean.
IEFLUENCE OF A FOREST ON TIIE TEXPERATURE OF
AN AIR CURRENT.’
L’abb6 I h n m LALIN.
[Dated: Viev1L-e (Cdte-d’Or), Mar. 20,1913.J
* * * My observations are here confined to the single probleni of what influence a wooded region may esert on the tem erature of a current of air.
Vievigne in the C6te-d’Or has a width of about SO0 me- t,ers. Two thermometers, graduated to one-tenth degree [centigrade] were set up on the eastern and western mar- gins at a distance of about 30 meters from the wood. At each observat.ion their readings were checked against the reading of n wliirlecl thermometer. Between May 15 and September 30 I made 70 observa- tions at various houis but most often in the forenoon. The results are as follows:
EAST wind, 17 times: 011 the E. margin the thermonieter dwaya
showed rexlinga 0.3’ to 0.8OC. highhcr than those on the W. margin. WEST wind, 2G tinlea: The t,hernionirt.er on the E. or downdream froin the wood bhowed rcutliiqs 03‘ to 0.75OC. lower than thoee on the W, niargin. RAIN, S times: Wind wx5 W. or SW., but the temperature was the same on either margin of the wood.z CALMS or.the wind did not blow across the wood from one station to the ot.lier, 19 tinies: The thermornetelv were in accord.
I conclude that the current of air has cooled in passing through t.his thin he-curhin. On esaiiiining the figures it seeins to me that one is led t,o conclude that t,his pipclification in t,emperaturc ig quite independent, of the initmid t.einperature uf the air and depends solely on t.!ie velocit.7 of t,he wind. T!ie lighter the wind, tlin greater is !.he diflerence. The niasiniiini dif-
ference of 0.S”C. correspoiided with a wind of velocity 3 on
The forest of P our (Bois du Four) between Spoy and
1 .Irror. Fmnr. pour If.\\,. de^. sri.. (’ompte rpndii de lo 12mr s m . Tunis, 1913: Nota
I T ~I ; IS rcsdilg explained as t le result of the lower calorific rsprity ofnater.--dulAor. et Yttmp?ire<. l’xis. 1\11 1. py. 242-54:i.