THE SCIENTIFIC MONTHLY JANUARY, 1919 WEATHER CONTROLS OVER THE FIGHTING DURING THE AUTUMN OF 19181 By Professor ROBERT DeC. WARD HARVARD UNIVERSITY HE Allied advance on the western front, which began on THE July 18, continued into the autumn with remarkable success until the ending of the war. Almost every day brought the news of a gain of territory; of the recapture of towns and villages; of the taking of prisoners and of guns. It seemed as if weather conditions, however unfavorable, could hardly make any difference in the carrying on of so aggressive a campaign, yet the autumn of 1918 was, in many respects, the most critical season, meteorologically, of any period of equal length during the whole war. It is easy to understand why this was the case. In the preceding years of the war, the winter storms, and cold, and mud on the western front necessitated a decided slackening of military operations between about the middle of November and early December. This happened in spite of emphatic 1 Continued from THE SCIENTIFIC MONTHLY for October, 1918, p. 298. Author's Note.-This series of papers on the weather factor in the Great War comes to a conclusion with the signing of the armistice by Germany. In the preparation of these articles, published in THE SCIENTIFIC MONTHLY and elsewhere, the writer had two things in mind. It was his belief that, as a part of the scientific history of the Great War, as full an account as possible should be kept of the meteorological conditions which affected the operations on all the battle-fronts. The other object was a practical one. It was felt that a discussion of the climatic conditions of the various war zones, and of the meteorological difficulties which were likely to affect, and which did affect, military operations, might be of some help in our own preparation for and conduct of the war. The facts set forth in these papers were collected from all available, reliable sources of information, chiefly the official headquarters' despatches, and the letters of well-known war correspondents. Later, and more complete, information may indicate that some of the statements which the writer has made should be modified, but it is his belief that what has been included is essentially complete and essentially correct. 290365 predictions, previously made by the military commanders, that the fighting would "continue as usual throughout the winter." The 1918 summer and autumn campaign on the part of the Allies was perfectly clearly a neck-and-neck race with the weather. It was the business of the Allies to force an overwhelming defeat of the German armies during the few remaining weeks of "fighting weather," and to make it impossible for the enemy to postpone the final decision until after another winter of relative inactivity. Again, in case a definite military decision should prove unattainable before winter, it was clearly to the advantage of the Allies to push on, beyond the area of destruction and desolation left by the Germans during the earlier part of their retreat, where there were no houses or shelters of any kind and no fuel, to the towns and large cities of eastern France and Belgium. Here adequate provision for billeting the soldiers could be made. The Hindenburg Line itself, with its elaborate concrete shelters and dugouts, was an important objective before winter, for this same reason. Mr. Charles H. Grasty, the well-known New York Times correspondent, in a cabled despatch from Paris, dated September 11, reported having asked a French military authority why the Allied troops did not rush ahead and crush the Germans at once. The reply was: There's one Generalissimo whom all belligerents take orders from, General Mud. If we could continue summer weather conditions another three months, we might get a decision. But it's unsafe to reckon on more than five weeks of good offensive weather. From the Somme to the Channel the character of the soil renders the mud the worst in all creation after the autumn rains begin in good earnest. The Germans, on their part, had every reason for prolonging the fighting until the advance of winter should delay the enemy pursuit, and bring a cessation of active operations. Germany would then be in a position to rest and to reorganize her forces, and to suggest peace negotiations on the basis of a stalemate on the western front. Both sides were thus fighting with the strongest possible meteorological pressure behind them. For both sides, everything depended on the time of the setting in, and upon the severity, of the winter. During the first days of September, the despatches mentioned the "unprecedented dryness" of the season as having been remarkably favorable for the movement of the Allies' troops, guns, tanks and supplies. In the absence of direct meteorological records from overseas, it is impossible to determine whether the term "unprecedented dryness" was war ranted, but it is clear that the roads were in good condition and that the Germans tried to hamper the Allied advance by flooding, wherever possible. The autumn rains were, however, not long delayed. For about a week, following September 8, heavy storms and chilly winds swept the entire battle area, slackening the progress of the Allies but not stopping their steady, although slower, advance. The men were drenched to the skin, and "felt the wind like a knife-blade." Yet there was a blessing in the rain, well recognized by some of the troops, for it laid the dust which was blowing from the battlefields covered with dead bodies of men and of horses, and it prevented the explosion of many shells which struck in pools of water. As the milder and more peaceful weather of summer on the western front gradually gives way to the stormier and more turbulent autumnal types, it is inevitable that active military operations should be oftener slackened, or even entirely interrupted. The fighting conditions are less favorable. The weather changes are more frequent and violent. The rain is more chilling, and snow and sleet begin to fall. Observation, on the surface or in the air, becomes more difficult, often even impossible, owing to clouds, or mist, or fog. Gunfire becomes inaccurate. Lower temperatures, especially during the autumnal nights, cause discomfort or suffering, and bring calls for warmer clothing and for fires. The traditional mud of Flanders makes the most serious trouble during the autumn rains, which are characteristic of that region. Flanders mud has played its part in every war fought over this same territory throughout history, and has over and over again proved a serious handicap in the present war. This mud is most troublesome in the colder months, for storms are then most, and spells of fine weather then least, frequent. The rains on the western front are not unusually heavy in the sense that they give a large annual rainfall, but they come fairly steadily throughout the year; the country is mostly very flat and poorly drained; the soil is quickly water-logged, and the trenches and shell-craters serve as so many reservoirs for collecting water. "Seas of mud," "quagmires," "morasses," "bogs" are expressions used to describe conditions which have prevailed since the war on the western front began. Incessant labor must be expended to keep the roads in condition for traffic. The rivers are frequently in flood, carrying away bridges and turning the lower lands into temporary shallow lakes. The relation between the weather and military operations, especially in autumn and winter, is like a see-saw. Spells of stormy weather and of deep mud mean tremendous difficulties of transportation and of troop movements, and hence involve a slackening of operations. Spells of fine weather mean greater aerial activity; more intense artillery action, and more favorable conditions for all movements. With the progression of the seasons, from summer to fall, it was inevitable that what has happened in the past four years on the western front would happen again in the autumn of 1918. There is no reason to suppose that the months of September, October and November of the present year were any more unfavorable, or brought any more rainfall, than they normally do, although the official despatches, and the war correspondents' cabled letters, lay unusual emphasis upon meteorological handicaps. This fact is, however, doubtless due to the intensity of the fighting, and to the tremendous effort which the Allied forces were making to bring the war to a successful ending before winter set in. It would be a tedious repetition to enumerate here all the many cases in which weather conditions controlled the military operations on the western front during the past autumn. The rains; the chilling winds; the low clouds; the fogs; the cold nights; the mud; the water-filled shellcraters; the flooded rivers; the swamps-all played their part. Sometimes weather conditions favored the enemy; sometimes they favored the Allies. On the whole, every bit of delay resulting from stormy weather and difficulties of transportation worked in favor of the enemy, for it gave him just so much more time to organize his retreat and remove his supplies, and it hampered just so much the Allies' progress in their pursuit of the retiring Germans. The successful elimination of the St. Mihiel salient by French and American troops just before the middle of September, although it occurred early in the autumn, furnished striking illustrations of the meteorological difficulties with which the armies had to contend. The advance was begun early in the morning after a rainy night, in a driving rain and mist which made aerial observation difficult, and was followed by a strong westerly wind which hampered balloon and airplane work. The roads were deep in mud, and the fields soggy. The movement of heavy guns and transports was very difficult, the mud proving too much for many of the tanks, although these were small and relatively light, and had a wide tread. "The infantrymen slipped and waded in pursuit of the retreating enemy." In spite of the bad weather, American bombers did effective work, driving down enemy airplanes and balloons and attacking German supply trains. The main road |