The creeping/rolling barrage is a slowly moving artillery attack acting as a defensive curtain for infantry following closely behind. The creeping barrage is indicative of the First World War, where it was used by all belligerents as a way to bypass the problems of trench warfare. It did not win the war (as once hoped) but played an important role in the final advances.
The creeping barrage was first used by Bulgarian artillery crews during the siege of Adrianople in March 1913, over a year before the war began. The wider world took little notice and the idea had to be re-invented again in 1915-16, as a response to both the static, trench-based, warfare into which the swift early movements of the First World War had stalled and the inadequacies of existing artillery barrages. People were desperate for new methods, and the creeping barrage seemed to offer them.
The Standard Barrage
Throughout 1915, infantry attacks were preceded by as massive an artillery bombardment as possible, intended to pulverize both the enemy troops and their defenses. The barrage could go on for hours, even days, with the aim of destroying everything under them. Then, at an allotted time, this barrage would cease - usually switching to deeper secondary targets - and the infantry would climb out of their own defenses, rush across the contested land and, in theory, seize land which was now undefended, either because the enemy was dead or cowering in bunkers.
The Standard Barrage Fails
In practice, barrages frequently failed to obliterate either the enemy's deepest defensive systems and attacks turned into a race between two infantry forces, the attackers trying to rush across No Man's Land before the enemy realized the barrage was over and returned (or sent replacements) to their forward defenses… and their machine guns. Barrages could kill, but they could neither occupy land nor hold the enemy away long enough for infantry to advance. Some tricks were played, such as stopping the bombardment, waiting for the enemy to man their defenses, and starting it again to catch them in the open, only sending their own troops later on. The sides also became practiced at being able to fire their own bombardment into No Man's Land when the enemy sent their troops forward into it.
The Creeping Barrage
In late 1915/early 1916, Commonwealth forces began developing a new form of barrage. Beginning close to their own lines, the 'creeping' barrage moved slowly forward, throwing up dirt clouds to obscure the infantry who advanced close behind. The barrage would reach the enemy lines and suppress as normal (by driving men into bunkers or more distant areas) but the attacking infantry would be close enough to storm these lines (once the barrage had crept further forward) before the enemy reacted. That was, at least, the theory.
Apart from Adrianople in 1913, the creeping barrage was first used at The Battle of the Somme in 1916, at the orders of Sir Henry Horne; its failure exhibits several of the tactic's problems. The barrage's targets and timings had to be arranged well beforehand and, once started, could not be easily changed. At the Somme, the infantry moved slower than expected and the gap between soldier and barrage was sufficient for German forces to man their positions once the bombardment had passed.
Indeed, unless bombardment and infantry advanced in almost perfect synchronization there were problems: if the soldiers moved too fast they advanced into the shelling and were blown up; too slow and the enemy had time to recover. If the bombardment moved too slow, allied soldiers either advanced into it or had to stop and wait, in the middle of No Man's Land and possibly under enemy fire; if it moved too fast, the enemy again had time to react.
Success and Failure
Despite the dangers, the creeping barrage was a potential solution to the stalemate of trench warfare and it was adopted by all the belligerent nations. However, it generally failed when used over a relatively large area, such as the Somme, or was relied upon too heavily, such as the disastrous battle of the Marne in 1917. In contrast, the tactic proved much more successful in localized attacks where targets and movement could be better defined, such as the Battle of Vimy Ridge.
Taking place the same month as the Marne, the Battle of Vimy Ridge saw Canadian forces attempting a smaller, but much more precisely organized creeping barrage which advanced 100 yards every 3 minutes, slower than commonly tried in the past. Opinions are mixed on whether the barrage, which became an integral part of WW1 warfare, was a general failure or a small, but necessary, part of the winning strategy. One thing is certain: it wasn't the decisive tactic generals had hoped for.
No Place In Modern War
Advances in radio technology - which meant soldiers could carry transmitting radios around with them and co-ordinate support - and developments in artillery - which meant barrages could be placed much more precisely - conspired to make the blind sweeping of the creeping barrage redundant in the modern era, replaced by pinpoint strikes called in as needed, not pre-arranged walls of mass destruction.