J N e Great Historical Events That Were De p a~ Significantly Affected by the rsrSSSS Weather. Part 11: Meteorological Jerusalem lsrael Aspects of the Battle of Waterloo* Abstract Napoleon's forces. The emperor was forced to sign his abdication (April 1814) and the victorious allies ban- The Waterloo Campaign extended from 15 to 18 June 1815, with ished him into exile on the island of Elba, off the west the decisive Battle of Waterloo taking place on the 18th. The coast of Italy. The French Senate reinstated the Bour- campaign involved the "Army of the North" of Napoleon on the one hand, and the Anglo-Dutch and Prussian armies on the other. The bon dynasty in the person of Louis XVI's brother, latter were commanded, respectively, by the Duke of Wellington and styled as Louis XVIII. However, before long, person- Prince Blucher. A shallow but active low and associated warm and ages loyal to Napoleon sent him messages informing cold fronts crossed the battle area on the 16th and 17th. him of dissatisfaction in the country and suggested his The weather had important effects on the battles. On the 16th, return. On 20 March 1815, the former emperor entered in a battle between part of the French army and part of the Prussian army, at the village of Ligny, about 40 km south-southeast of Paris, where he was received by enthusiastic crowds. Brussels, thunderstorms connected with the passage of the afore- With this began Napoleon's "one hundred days' rule." mentioned warm front made the use of muskets impracticable. Representatives of the powers opposed to Napo- However, the most important weather effects developed on the leon were holding the "Congress of Vienna" at the time, 17th and during the night from the 17th to the 18th. Violent thunder- and decided then and there to form a new coalition storms occurred early in the afternoon of the 17th close to Ligny, while Napoleon was in the process of attacking the Anglo-Dutch against him. Their armies were to invade France from force at Quatre Bras. The rains turned the ground into a quagmire, the north, east, and southeast. In conformity with his making it impossible for the French artillery and cavalry, and even usual strategy, the emperor wished to deal separately for the infantry, to move across the fields in extended order, as with each army of the coalition. He decided to attack required by the emperor. The French advance was so greatly first the enemy closest to Paris: namely, an Anglo- slowed down that Wellington was able to withdraw his lighter force to a better position near Waterloo. Thus, the Anglo-Dutch force was Dutch army, commanded by the Duke of Wellington, almost completely preserved for the decisive battle of the next day. and a Prussian army, commanded by Prince Blucher. The rainshowers of the 17th and the night from the 17th to the These two marched into Belgium in June 1815. Napo- 18th softened the ground to an extent that, on the morning of the leon crossed into Belgium on 15 June at the head of his 18th, Napoleon and his artillery experts judged that the battle—the army, the "Army of the North" (Armee du Nord), and on Battle of Waterloo—could not be started before a late hour of the forenoon [1130 local standard time (LST)]. Until the arrival of the the 16th struck at the Prussians at Ligny, about 40 km Prussian force, about 1600 LST and later, the battle tended to go in south-southeast of Brussels. Events of the remaining favor of the French, but the Prussians turned the tide of the fighting. days of the "Waterloo Campaign," which ended with The paper quotes judgments of military historians on the signifi- the Battle of Waterloo on the 18th, are described very cant effects of the weather. Some historians believe that, had briefly in the following sections, where emphasis is put Napoleon been able to begin the attack earlier on the 18th, the battle on the weather effects on the battles. would have ended in a French victory. 1. Antecedent events 2. Weather of the days leading to the Battle of Waterloo, 15-18 June 1815 Early in 1814, armies of some member states of the anti-Napoleon coalition invaded France and defeated According to information received from the Belgian Royal Institute of Meteorology in Brussels, there were *Part 10, "Crop Failure in Britain in 1799 and 1800 and the British no regular meteorological stations operating in Bel- Decision to Send a Naval Force to the Baltic Early in 1801," was gium in 1815. However, Vanderlinden (1924, 302- published in the February 1992 Bulletin (73,187-199). See Part 9 304) compiled a brief descriptive account of the weather (71, 33-41) for a complete list of the series up to and including Part 8. + in the country in 1815, and, in a one-sentence-long Visiting with the Department of Meteorology, University of Copen- hagen, since 1986. statement regarding June, he writes that the begin- ©1993 American Meteorological Society ning of the month was rather rainy and that thunder- Bulletin American Meteorological Society 413 Unauthenticated | Downloaded 10/09/21 03:50 PM UTC storms occurred on the 12th, 17th, and 20th. Memoirs day was rainy, with thunder at 1000 LST. The weather and letters of participants of the Waterloo Campaign of the 18th was very cloudy, but no rain is mentioned. (to be quoted below) record that there was a major The Haarlem data show a rise of 3°C in temperature thunderstorm in the general area of Waterloo on the from the 16th to the 17th; more significant is (see the 16th in the late afternoon/early evening, and that the next paragraph) the drop of about 4.5°C in the tem- thunderstorm that burst on the 17th early in the after- peratures for 1300 LST from the 17th to the 18th. noon was especially violent. The showers and rains of Figure 1 is a synoptic map for western and north- that storm continued, with some intermissions, until western Europe and the northeastern North Atlantic about 0800 local standard time (LST) on the 18th, the for the 17th, the day of the most significant weather in day of the Battle of Waterloo proper. The showers and the battle area. The map was prepared by John rains turned the ground into a quagmire, severely Kington, Climatic Research Unit, University of East impeding the trafficability of the fields not only for the Anglia, Norwich, England, based on the data bank artillery and cavalry, but the infantry as well. This will built up at the unit; construction of the map was aided be described in the following sections. by Kington's study of weather conditions in western In view of the absence of regular meteorological Europe in the late eighteenth century (see Kington stations in Belgium at the time, we have examined the 1988). The weather of that day had the most serious data of the meteorological stations at the Paris Astro- and fatal consequences on Napoleon's army. nomical Observatory (PAO), at Haarlem and Zwanburg If we assume that the depression and the cold and in the Netherlands, and at two stations in the London warm fronts of Fig. 1 moved essentially eastward (as area (Greenwich and Camden). Table 1 lists some of they usually do), then the data of Table 1 and the the data of the PAO and Haarlem. The printed record pressure and front configurations of Fig. 1 can be of observations of the PAO for the month lists the connected in a satisfactory manner. It seems prob- highest and lowest values of the pressure of each day, able, and perhaps even certain, that the thunderstorm as well as at midday; air temperatures are stated only and showers of the 16th late in the day in the battle for noon. The weather is recorded for three periods of area (of the Battle of Ligny, Ligny being a village about the day: "morning," "midday," and "evening." Haarlem, 25 km from Waterloo and nearly 40 km to the south- on the other hand, records, among others, the air southeast of Brussels, see Fig. 2; the battle was fought temperatures at 0800, 1300, and 2200 LST. between a French force and a Prussian force) were In Table 1 we reproduce the highest and lowest connected with the passage of the warm front of the pressure values at the PAO, as well as the remarks on depression. This suggestion is supported by reports of the weather; in the case of the Dutch station, we list its participants of the battle, which state that on the 17th, temperatures and the all too brief notes on the weather. by 1300 LST, the air was sultry: apparently, the battle The latter do not specify the hours at which the area fell into the warm sector of the low pressure weather stated prevailed. system. It is seen in Table 1 that Paris reports a drop in The great thunderstorm and showers/rains of the pressure from the 16th to the 17th; the maximum value 17th were in all likelihood associated with the passage of the day lowered by over 5 mb. The weather of the of the cold front of the low. This is corroborated by the TABLE 1. Meteorological data for the days of the Waterloo Campaign, 15-18 June 1815. Date in Paris Astronomical Observatory Haarlem June 1815 Pressure (mb) Weather Temperature (°C) at LST Weather Max. Min. Morning Midday Evening 0800 1300 2200 15 1009.3 1001.5 cloudy very cloudy fine 15.6 19.4 15.6 showery, very windy 16 1009.8 1003.7 cloudy overcast rain 15.7 22.2 15.6 somewhat brighter 17 1004.2 1001.8 very cloudy rain, thunder intermittent 21.2 21.1 15.6 warm, showers, at 10 rain then cloudy 18 1005.9 1004.6 very cloudy very cloudy very cloudy 15.0 16.7 14.4 rain with hard wind 414 Vol.