Weather – A

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Readers are invited to contribute shortquestions on any meteorological topic. We will endeavour to obtain answers to allsubmitted questions.

Huge, heavy andhistoric hailstones

The following item was originally submitted toPaul Hudson, the BBC weather forecaster forYorkshire. We thank Paul for forwarding it toWeather and also Jonathan Webb for writingthe reply.

The following accounts of a dramatic butlocalised storm in the east of this parish on31 August 1810 have recently beendiscovered.

The first reference is found in an unpub-lished chronicle of a milling and farmingfamily associated with Stone Mill, nearRoche Abbey in the ancient parish of Maltby.(It may be original or it may, possibly, incor-porate matter from a local press report. Itwas transcribed by Mike Sparling and isreproduced with his permission.)

31 August 1810

There fell at Stone an extraordinary showerof hail (or rather ice) and rain; accom-panied by the most tremendous thunderand the most vivid flashes of lighteningimaginable; the hailstones measured twoand one half inches diameter, the largestway, they being rather in the form of aturnip flattened on two sides, and weresolid hard pieces as if they had been cutfrom a block. It fell as heavy at Stone asanywhere but extended to Stainton,Sandbeck, the middle of Sam Froggatsfarm and to Jos. Jenkinson's house; withinwhich circuit or rather farther it destroyedalmost all the corn upon the ground, thatwhich was cut being mainly all thrashedout, and the uncut broken down andburied in the earth. This was followed by alarge flood, the largest that could beremembered.

Two further accounts are found in unpub-lished letters of Richard, sixth Earl ofScarbrough, sent from his house atSandbeck Park in Maltby Parish to MrDungworth, his Lincolnshire steward, wholived at Glentworth near Lincoln where LordScarbrough had another house. By kindpermission of the Trustees of the Earl ofScarbrough’s 1979 settlement, I have tran-scribed these from originals in the LumleyArchive at Sandbeck.

Sandbeck, Sunday, 2 September 1810

….you will grieve to hear that thisParticular Domain, was visited on FridayNight about 7 o’Clock with the severestStorm of Thunder, Lightening, Rain & hail,ever known in the memory of the oldestman in this Neighbourhood Every Skylight& several windows in this House weresmashed, 100ds Panes of Glass in the GreenHouse; Pinery's [i.e. pineapple pits (AR)] &vineries broke: One Hail Stone picked up,that night in the Garden, measur'd 7 Inches& 3/4s [In circumference], Many from 4 to 6Inches, and the next Morning tho' a veryHot one, many Barrows full of hailstones aslarge as Pigeon Eggs were picked up as late,as 10 o' Clock: The Crops of Wheat, Barley,Potatoes, Turnips & Cabbages at my Farm,are almost totally destroy'd. I cannot reck-on my Loss in everything at less than£1500, (a heavy Business after all myBuilding here) but Thank God! no Liveswere lost, and the Influence of the Storm,was very narrow, so that I believe the neigh-bourhood has suffered very little.

Sandbeck, Sunday, 16 September 1810

Amongst other Damage, which the Stormhas done me, It has almost totaleydestroy'd my Game, on the District Wheremy Gamekeepers us'd chiefly to kill for theTable- This being the Case, and as I shallhave a large party here, before, during &after Doncaster Races, Pray Tell myLincolnshire Gamekeepers, That I shall beparticularly oblig'd to Them, if They willsupply Me, as amply, as possible withGame, the End of this ensuing Week, & theEnd of the week after That, again- Yr sin-cere Wellwisher Scarbrough

These reports, which would now be thestuff of wall-to-wall news coverage, werewritten by very level-headed men for privatepurposes and the sixth Earl was certainly notgiven to hyperbole! I am fascinated both bythe intensity of the storm and by its tightgeographical limits. Its western (described)limit is a farm just above Roche Abbey (cen-tred on SK 542900). By process of elimina-tion, still to be confirmed by detailedresearch, I deduce that Sam Froggat’s farmwas most probably located south of Stoneon the southern bank of Maltby Dike andmainly in Firbeck Parish. Sandbeck HomeFarm was then centred on SK 564896. TheSandbeck Estate (which includes RocheAbbey) then stretched west towards Maltbyvillage, north into Stainton parish, east tothe present A60 and north-east into Tickhill.Much of this land was well wooded so thegame would have been destroyed at anypoint within the compass described in thefirst account.

Is it possible, on the basis of the availableevidence, meteorologically to identify whatwas going on? Sadly, nobody painted awatercolour!

Alice RodgersChairman,

Maltby Local History Society,South Yorkshire.

Jonathan. D. Webb, Tornado andStorm Research Organisation,Oxford replies:The Tornado and Storm ResearchOrganisation (TORRO) researches British andEuropean hailstorms and we have a data-bank of approximately 2000 significantevents.

Hailstorms of this magnitude require:

(a) a very steep temperature lapse ratethrough a deep layer of the troposphere, thevigorous convective buoyancy aloft provid-ing the potential for cumulonimbus cloudsof great height. This upward momentumcan produce an appreciable depth ofunfrozen (supercooled) cloud above the 0 °C level, favourable for hailstone growth.

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Typically, a stable layer puts a temporary ‘lid’on convection allowing the build up ofConvective Available Potential Energy(CAPE) which is later explosively released(Dudhia, 1996); for instance, by strongsurface heating, forcing ahead of a coldfront, or convergence within a pre-frontalheat low or a sea breeze ‘front’; (b) signifi-cant vertical wind shear enabling the forma-tion of a self propagating, long-lasting stormsystem (Mason, 1985). Because of the latter,severe hailswaths, while usually narrow,quite often extend for over 50 km and occa-sionally to 100 km or more in length. The1810 event appears more localised.

There are a few contemporary weatherregisters for 1810. At the Royal Society inLondon, thunder and lightning was report-ed overnight on 30/31 August. At 0700 h thewind was easterly, force 1 and at 1400 h theentry was: SSE1, temperature 27 °C. Furthernorth at Derby the comparable weatherdiary records a maximum of 26 °C, a souther-ly wind at 1400 h and thunder. From thelimited information available one can infer aplausible sequence of weather as follows:

Thundery rain occurring from extensive,deep unstable medium level cumulusovernight as a plume of very warm airpushed northwards (ref. the marked wind

veer reported); further destabilization of thestagnant warm air mass on 31 August by (a)surface heating (and possibly further warmadvection from the south at low levels) and(b) cold air advection aloft, overriding thevery warm air, ahead of an upper troughwhich was probably associated with anincreasing south-west wind at mid-levels.Storm-steering winds are usually attributedto the flow at between 700 and 500 mb andthe storm track described appears to havebeen from south-west to north-east, i.e.Roches Abbey to Sandbeck and Stainton.

It may be noted that hailstones of irregu-lar dimensions, as described here, arerelatively common; information in the aboveaccounts indicates that about 50 mm wouldbe a fair estimate for the mean diameter ofthe largest pieces of ice in this 1810 storm.This and the reported damage indicate anintensity of H4–H5 on the International Hailintensity scale (see Weather, 60, p 11 andhttp://www.torro.org.uk/TORRO/severeweather/hailscale.php).

Since 1800, this is one of only two suchintense hailstorms to affect South Yorkshire,the other ironically occurring less than ayear later on 12 May 1811 in the Sheffieldarea. However, several comparable eventshave affected neighbouring counties of

West Yorkshire (e.g. 2 July 1968) andNottinghamshire (e.g. 14 July 1975).

Since 1800, 93% of (reported) destructive(H5+) storms in Great Britain have occurredbetween May and August with a clear peakfrequency in July. The above database indi-cates that storms of this intensity haveoccurred in 81 of the past 205 years.However, even in the most prone countiesof the east Midlands the incidence has beenonly around three storms per 1,000 km² per100 years.

Acknowledgement I am grateful to Ian MacGregor at theNational Meteorological Archive, Exeter, forchecking the Derby diary.

ReferencesDudhia J. 1996. Thunderstorms: Part 1.Weather, 51: 371–376.

Mason BJ. 1985. Progress in cloud physicsand dynamics. Recent advances inMeteorology and Physical Oceanography,Royal Meteorological Society.

doi: 10.1002/wea.7

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A lenticular cloud over the Nef Valley, Chilean Patagonia, March 2006. (© Chris Lucas.)