Lessons Learned in 1939-40 Winter War

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Winter War -  How the Red Army Finally Defeated the Finns

The Setting is the Enemy

The peculiarities of the Finnish theater of war that caused the greatest combat difficulties were the absolute lack of roads and the close character of the terrain which, with its vest zone of virgin forests, is so very different from the European landscape in latitudes farther south. The Karelian woods are under no forestry management such as is commonly applied in central Europe. The primeval forest is the result of natural reseeding. Old and young stands of trees are intermingled and frequently give rise to impenetrable thickets. This boundless forest is virtually unexplored. Throughout the trackless, desolate region, deepest solitude and deathly silence reign supreme. Lakes, swamps, moors, and loose rock are characteristic of the Karelian landscape. Although on the Karelian Isthmus (the corridor between the Gulf of Finland and Lake Lagoda) and in the area between Lake Lagoda and Lake Onega the woods in some places are very dense and include old stands of trees, the timber becomes lighter and weaker the farther one goes north, until at last only scattered trees and bushes extend upward from an inextricable tangle of large rocks. In the Far North, rocky ground covered with reindeer moss, lichens, and blueberry, cranberry, and juniper bushes predominates in the wilderness. In the part of Karelia between Lake Onega and the White Sea, the tree line is about five hundred feet above sea level. Birches grow on the slopes between the conifer covered dales and the bare tops of the mountains, which are less than a thousand feet high. The conifers disappear completely north of the Arctic Circle. This is a favorable region for birch forests, so characteristic of Lapland, with their short trunks often branching out like bushes. In the Petsamo region the completely treeless tundra extends up to the coast, where it changes into bare shingle along the Arctic Ocean.

This is a heroic landscape which has remained completely untouched by modern civilization. Since the dim past little or nothing has changed there. As in those days of long ago described in the songs of the Finnish epic, the “Kalevala,” the hunter and fisher, the Lapp nomad with his reindeer herds, the individual loving solitude lives in the primeval wilderness, constantly struggling with the forces of nature.

The Operational Mobility of Army Corps and Divisions

Before World War II the Finns estimated that they could adequately defend their country. The more than 1,200 kilometers southeastern and eastern border of Finland which was primarily considered to be the future theater of war, had a very sparse network of roads, which would restrict the utilization of strong forces. It was estimated that the enemy could concentrate at most 15 divisions as compared to Finland’s 10 divisions.

From the approximately 100 kilometers wide Karelian Isthmus, four railroads and 3 to 10 highways led to the northwest. The railroads were single tracked; the roads had a gravel surface and were so narrow that a two way truck traffic was barely possible. The surface of the roads was estimated to be so poor, that only one infantry division with reinforcements could advance along the direction of one road.

In the part of Karelia just north of Lake Ladoga, an area 100 kilometers wide, one railroad and four highways led from east to west. The border from Lake Ladoga to the Arctic Ocean was approximately 1,100 kilometers long. A total of six roads ran from here to east and west. These roads were in a much poorer condition than those on the Karelian Isthmus. Along these roads as well, the advance of only one division was regarded as possible. Since nearly 80 percent of the frontier region was covered by forests and 15 percent by marsh lands, the 200 kilometers wide sectors between the roads were uninhabited areas of forests, marshes and lakes. Seldom were the winters so intensely cold, that the ice on the marsh lands and the lakes would be strong enough to bear the weight of tanks, heavy guns and trucks.

At first, during the winter of 1939-1940, there was very little snow, but the temperature fell to -40°C. Nowhere was the snow cover as deep as one meter. The surface of the bad roads, the marsh lands and the lakes were so solidly frozen that they supported the weight of even heavy transport vehicles. The development of snowplowing equipment and of motor vehicles adequate for winter conditions made it possible for the enemy to use nearly 50 divisions in the final stages of the war. The situation became extremely critical on the coast of the Gulf of Finland, between Viipuri and Hamina, where seven divisions attacked across the ice of Viipuri Bay. However, the greatest surprise was that between Lake Ladoga and the Arctic Ocean, 11 divisions operated from the beginning of the war and 20 in the end. The enemy’s complete command of the air, 1,000 aircraft in comparison to 100, made possible the movements of dense and direct concentrations even on the ice flats.

The Finnish army corps and divisions did not derive much advantage from the increased freedom of operations, because they had very few motor vehicles and the existing road network was thus sufficient for their operations. On the other hand, the Finns had improved the armament, equipment and tactics of the infantry and continued to do so by improvisation. Primarily, the aim of these innovations was to use the forests and the climate to the best possible advantage. The key problems to solve were, first, how to survive in the severe winter weather in the uninhabited wilderness, and, second, how to operate in the deep forests flanking the roads.

Weather and Terrain Effects Upon Operations

Experiences gained during the Finnish-Soviet Winter War of 1939-40 had taught the following lessons:

First, the natural conditions along the frontier between Finland and the Soviet Union, the extremely extensive, pathless wasteland of the frontier region, the uneven terrain covered with loose rock and consequently passable only with difficulty, and the negligible development of roads are not suited to operations with large masses of troops of low mobility. Over broad stretches of country it is, in many cases, impossible to conduct operations involving large organizations, and in some instances, it is pointless.

Second, from the strategic point of view, the importance of the different sectors of the frontier region varies widely. Gain or loss of areas far removed from any kind of communication is of no decisive importance to the further course of the war.

Third, the characteristics of terrain and climate in the Far North are such that winter is the more favorable season for offensive campaigns, while summer is more suitable for defensive operations. Early and late winter are particularly favorable for attack operations; mid-winter with its deep snow is a less appropriate time for offensive warfare.

Fourth, the transitions from winter to summer and from summer to winter constitute the muddy periods when use of the roads temporarily ceases or is greatly limited. The muddy period in the fall does not last as long as that in the spring. Because of the hard granite soil of Finland and Russian Karelia, the roads usually dry out much quicker there than in southern Russia. In the Far North, the principal concern is the melting of the snow which has fallen during the winter. The Finns have great experience and have developed special techniques to keep the main highways free from snow and open throughout the winter for the use of mail trucks and buses. The effect of brief periods of rain, which in Russia proper turn the roads into a hopeless condition, is negligible in Finland and the border area. During the muddy season, especially in the spring, there is no chance for effective air support because it is impossible for units of any considerable size to take off from the completely flooded airfields. Provisions were made to maintain flying operations on a limited scale through installation of latticed wooden runways. In these cases, it was necessary to park the airplanes either on the runways or in their immediate vicinity. Such a procedure cannot be applied for organizations of any considerable size unless one accepts the necessity of expending enormous amounts of material and labor in the construction of latticed wooden runways and taxiing strips to the hardstands. Since both opponents were faced by identical conditions, air force activity, with only a few exceptions, was almost completely suspended on both sides during the muddy season.

The Horse Provides Tactical Mobility

Finnish farmers and lumberjacks were used to transportation with horses and sleighs in winter conditions. When hauling logs from the forests to the roads, the preliminary stage was to move on skis and open a trail in the woods, avoiding gorges, cliffs and steep rises. This was not too difficult, because the differences of level in the Finnish terrain are only about ten meters. When a few horses and a sleigh had moved along the trail, the worst ruggednesses could be noticed and avoided. A winter road was finally formed in the forest, along which a horse could pull a load weighing up to one ton.

In the pre-war winter maneuvers of the army, the methods of the farmers and the lumberjacks had been used. Sleighs, sleds and skis were chosen and developed in such a way that they could transport the heavy arms and equipment of the infantry in the roadless forests and across the frozen marshes. Light horse drawn artillery was loaded on sleighs or runners were fixed to wheels. Sleighs were much better for evacuating the wounded than vehicles on wheels in the summer. Transferring the traffic from roads to forests, in shelter from observation and air reconnaissance, offered new possibilities for surprising the adversary and reducing the advantage of his air superiority.

In 1939, there were about 500,000 horses in the country, but during mobilization the armed forces used only 20 percent of them. Because more than a half of the nearly 500,000 army reservists called up were farmers or lumberjacks, the number of skilled horsemen was equivalent to that of horses. Considering the fact that all the Finnish soldiers were used to winter conditions and to moving in the dense forests, the tactical mobility of the army was on a very high level. The capability of imaginative innovations and successful improvisations contributed to this tactical efficiency.

Effects of Snow, Ice and Frost on Operations and Firepower

The effect of snow, ice and frost on firepower could not be estimated beforehand. Not until after the experiences of the summer of 1941 and the battles of 1944 could the weakening impact of snow and frost on firepower be adequately observed. It has not been possible to measure exactly this impact, but those who have seen service in the wars of 1939-1945 calculate that snow and subarctic weather lessened firepower by at least one third or even by 50 percent.

First, deep snow reduces fragmentation in the same way as soft soil does. Frost affects primers, so that the number of dud shells grows considerably. The power of an exploding shell is somewhat smaller in subarctic weather, and the accuracy of fire weaker because the powder burns more slowly. Cold weather also increases the mistakes of an observer directing artillery fire. Frost does not have a direct effect on the firepower of the light arms of the infantry, but accuracy of fire suffers due to the human factor; that is, the effect of sub-zero weather on the soldier. Automatic weapons and machine guns are heavily affected by freezing weather.

According to the nearly unanimous opinion of men who saw service in all phases of the war, the enemy had much weaker firepower and worse accuracy of fire than the Finnish troops, accustomed to and prepared for winter conditions. There was an especially big difference in the power and accuracy of the light arms of the infantry. The Finns had to pay attention to the effects of winter and severe cold in the yearly winter contests, in which the army and the Civic Guard took part. In winter conditions, it was necessary to keep especially the automatic weapons very clean, to prevent freezing of the moving parts. Sometimes arms had to be cleaned with petroleum when no light sewing machine oil was available. This kind of oil would not freeze and had a viscosity rate which made it suitable for all types of automatic arms. Besides the freeze endurance of the usual lubricating oils, it was necessary to test and pay attention to the anti-freeze capacity of other fluids and oils as well to keep the weapons in action. For the handling of weapons, knitted gloves, with only the trigger finger free, were found most suitable, these had been used by hunters for decades.

Since the Finns were accustomed to the climate, they clothed sensibly when winter set in. They knew how to dress when the temperature dipped several degrees below zero. The field uniform of the soldier was designed to make him endure snow and freezing weather. The white dresses of the soldiers, covering the uniforms, had been developed for winter warfare.

The most difficult problem (solved, however, already in the 1930’s) was how to camp and find shelter in the bitter winter of the wilderness. A tent for the use of half a platoon, approximately 20 men, was designed; this could be folded into a small and easily handled bundle. A portable box stove was enough to keep the tent warm even if the temperature fell to -40°C. On the stove coffee and food could be easily prepared. The new tent made military operations possible even in uninhabited areas.

Finnish “Motti” Tactics

Because the Finns had insufficient forces and equipment for classical air, tank and artillery operations, the enemy had to be forced to attack under the worst possible conditions for them. The terrain and the road network favored the Finns. The enemy divisions (or division) advanced along the road in a giant column, strung out over 100 kilometers. The road was flanked by a 100-200 kilometer wide, uninhabited wilderness, covered by forests, with numerous lakes and marshes.

The battalions engaged in delaying actions aimed at bringing the enemy’s forward group to a halt in every possible location. At the same time, where the terrain and conditions were favorable, the enemy column was broken up and isolated into small units. The breaking up of the column was done by strike forces that advanced from the cover of the flanking wilderness toward the road used by the enemy. Short distance slicing operations were performed by mobile ski units; ammunition, mines and explosives were either carried along or pulled in sleds. The wounded were also evacuated in sleds. In medium distance, 10-20 kilometers, road cutting operations, a winter road was prepared and ammunition, mines and explosives as well as the wounded were moved through the woods by horses and sleighs. In long distance operations, a road was plowed at night on the snow covered ice of the marshes and lakes, and the troops and equipment were transported to within a distance of 5-10 kilometers of the enemy positions.

At the end of the winter (or ice) road, an easily defensible logistics base was established. Often it also served as an advanced dressing station, headed by a medical doctor. The attack, with the objective of cutting the road, was done on skis, while the equipment was carried and pulled on sleds, generally in short distance operations and under fire from enemy infantry. Such a base might have included a mortar company or even a battery of field artillery, which, however, for the sake of secrecy, withheld their fire until the infantry reached its objective and the general assault commenced.

The blocking points on the road along which the enemy advanced were decided upon and marked on the map after careful planning and reconnaissance. Along the road, one or several small hills or outcroppings in the terrain, without any organized defense, were usually chosen as points to block the road. Another requirement was that if the enemy tried to move forward or retreat, the road could be easily cut and brought under fire. The most advantageous from this operational point of view were bridges and embankments which were difficult to bypass.

The assault upon the point, which had been chosen for the roadblock, was done in the most surprising manner, taking the best possible advantage of the terrain and darkness. After the initial reconnaissance, the commander of the strike force or the battalion advanced with the orientation and reconnaissance group within observing distance of the final objective. On the basis of the information gained, by observing and listening to the enemy and the traffic along the road, the commander ordered the attack to begin at the very moment when few enemy troops were in the target area. The battalions of a strike force or the companies of a battalion advanced directly to those points in the terrain, which they had to occupy. The sappers of the attack group destroyed the bridges and embankments at the blocking points and mined the areas the enemy had to cross when counterattacking. Often there was enough time to prepare an improvised fire plan and to dig in at least into the snow before the enemy counterattacked. Each minute that passed before the counterattack began was to the advantage of the attack group blocking the road. The fire plan of the artillery was usually prepared to cover the most dangerous direction, but fire was opened only when the enemy’s full counterattack began.

If the troops succeeded in completely surprising the enemy, as was often the case, effective counterattacks commenced only after several hours. Daylight favored the force that held the roadblock. The enemy’s fire was inaccurate, because the troops were well hidden in the terrain. The fact that the enemy formations were at a close distance, with Finnish forces between the isolated groups, made the use of heavy weapons difficult, while making it possible for the Finns to fully exploit the accuracy of their light arms. The more numerous the roadblocks, the longer it took for the enemy to launch their counterattacks and the more surely were they repelled.

The turning point in repelling the counterattacks was the separation of the tanks from the infantry following them. It was consequently important, that the positions of the infantry which blocked the road were in such rugged terrain or in such a dense forest, that the tanks were not able to drive inside them. If the positions fulfilled these requirements, the enemy’s infantry was either annihilated or driven back. Finally, those tanks which had passed through the minefields were destroyed by attacking them with gasoline bottles and TNT-charges. During the Winter War and partly even during the Continuation War, the number of anti-tank guns was so limited that they could be used only when the enemy launched an armored attack along an open road.

Since the enemy forces were not able to move away from and maneuver outside the roads and since the supplies dropped from the air were insufficient, the counterattacks were in the end hampered by the lack of ammunition and food. The effects of the Arctic temperatures and the lack of tents and stoves contributed to the annihilation of the enemy forces between Lake Ladoga and the Arctic Ocean. On the Karelian Isthmus the Finnish “motti” tactics could not be used because of the continuous front lines and the dense network of roads.

The Finnish Troops

During early and late winter, troops equipped with skis and akios can operate off the roads and bring along all that is really needed for existence and for combat; but they must leave behind everything that cannot be carried easily through primeval forest or rocky wilderness. The superior skill of the Finnish troops in covering long distances gave them high mobility and consequently a decided ascendency over troops of the Red Army in the Winter War.

The Soviet command recognized the great importance of using skis in fighting in the Far North. According to Finnish accounts, the Russians formed and trained special elite ski units in Siberia and concentrated them before World War II on the eastern border of Finland. These Soviet troops soon acquired great skill and during the war became almost as good as the Finnish ski units, whose marching speed is surprisingly great even in especially difficult terrain. Combat operations even in trackless regions, are executed much faster on skis in winter than on foot in summer. The open flanks of the Finnish-German sectors between Lake Onega and the Arctic Ocean could only be effectively protected by mobile Finnish ski patrol detachments. The fight against the Soviet partisans was carried on by the Finns with the passion of skilled and experienced hunters. It was most successful in winter when the enemy’s tracks could be followed in the snow, and they could be brought to bay.

The strength of the Finnish soldier lies in individual combat. The Finns possess an infallible instinct for finding their way in the dense growth of the pathless wilds. They are accurate trail readers and move noiselessly in the woods. Nothing is heard or seen of Finnish troops whether resting or marching, even from the closest proximity. Terrain training is of a very high order. A special technique for movement through woods has been developed and practiced so that the troops advance quickly, in the right direction and without losing contact. A Finnish company moves in the primeval forest just as smoothly and unerringly as a German company in the open landscape of central Europe. All Finns are enthusiastic hunters and sports lovers and fighting wakens in them all their hunting instincts.


The Finnish infantry is equipped with skis in winter. Accustomed from earliest infancy to move on skis during over half of the year, the Finn accomplishes marvels in covering long distances. The use of the simple Finnish toe binding enables the soldier to put on and take off his skis quickly. The enemy is approached on skis in small, well separated groups echeloned in depth. The crouching skiers, camouflaged in snow shirts, rapidly approach the enemy in short bounds. Just before the final rush, they quickly kick off their skies. Often the men drag their skis along, or else a member of the group gathers all the skis and brings them forward.

The Finnish cavalry in general had the mission of mounted infantry. The guiding principle in its training stressed encirclement and attack deep in the enemy flank. It was able to carry out this task because the Finnish horse was used to traveling even over difficult wooded terrain covered with rocky debris. In the winter the cavalry troops are also equipped with skis.

Training and organization of the Finnish artillery was primarily designed for combat in woods and achieved a high level of efficiency during the last war, despite the fact that the armament was to some extent old fashioned and lacked uniformity. Since opportunities for observation were limited in the wilderness, each battery, as a rule, needed several observation posts. Therefore, every battery had at least two forward observers. By means of a signal communication net specially organized for this purpose, every forward observer was able to deliver fire with all batteries of the regiment. In the defense it was even possible to deliver fire with all medium and heavy mortars. The forward observers of the mortars in turn were able to do the same. The forward observers were connected with the firing positions by wire and radio. Great stress was laid on surprise fires. Survey was well perfected and very rapid when the aiming circle was employed.

In tank combat the Finns lacked practical experience. Not until World War II did the Finns undertake to organize an armored division. The materiel consisted of captured Russian equipment, to which a few German tanks were added in the last year of the war. Training was based on German regulations. The Karelian Isthmus is especially favorable for armored operations. The Russians employed numerous tank units there in the Winter War and in the summer of 1944.

The technical and tactical aspects of Finnish signal communications were still in the first stages of development. The use of bare wire, occasioned by special conditions of combat in woods and the critical situation in the manufacture of field signal cable, was remarkable. For this purpose, a galvanized iron wire 2mm thick was strung overhead. In winter, if the situation was urgent, it was also possible to utilize the insulating property of completely dry snow by laying wire in the snow as a metallic circuit. Messenger dogs and carrier pigeons were not used in the Finnish army.

Forschungsmitarbeiter Mitch Williamson is a technical writer with an interest in military and naval affairs. He has published articles in Cross & Cockade International and Wartime magazines. He was research associate for the Bio-history Cross in the Sky, a book about Charles ‘Moth’ Eaton’s career, in collaboration with the flier’s son, Dr Charles S. Eaton. He also assisted in picture research for John Burton’s Fortnight of Infamy. Mitch is now publishing on the WWW various specialist websites combined with custom website design work. He enjoys working and supporting his local C3 Church. “Curate and Compile“
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