April 22nd, 1915

- For the past two days, German artillery has been shelling the town of Ypres, but otherwise there has been little activity in the salient.  It has been a pleasant spring day, clear with only a light breeze blowing from the northeast.  However, the idyllic conditions are also ideal for the long-planned German gas attack, and a new terror is about to be unleashed on the modern battlefield.

At 6pm the gas canisters are opened along the front held by the German XXIII and XXVI Reserve Corps, and in the evening breeze the yellow-green cloud slowly rolls towards the enemy line between the Yser Canal and Poelcappelle.  Here the trenches are held by the French 87th Territorial and 45th Algerian Divisions.  The French and colonial soldiers have no idea what the strange cloud approaching them is, and when it begins to seep into their trenches, pandemonium ensues.  The chlorine gas blinds and chokes, the lungs blistering and filling with fluid until the victim, unable to breath, dies.  The French and Algerians pay the price for the earlier dismissal of warnings regarding the German attack; the only choices they have is die or flee.  Survivors flee southward, choking and half-blinded, presenting a terrifying spectacle to the British and Canadian soldiers they pass by.

German chlorine gas drifts towards Entente lines during the 2nd Battle of Ypres, April 1915.

At 615, the German infantry attacks, following in the wake of the gas clouds.  In front of XXIII Corps, the gas attack was not entirely successful, and 45th and 46th Reserve Divisions have a hard fight before they are able to seize the village of Steenstraate, though later in the evening German forces are able to push across the Yser Canal at Het Sas.  On the other side of the German attack, the gas is largely ineffective in front of 51st Reserve Division of XXVI Reserve Corps, and the right of 45th Algerian Division and the left of 1st Canadian Dvision are able to put up stiff resistance before the Germans are able to seize the village of Langemarck.  In between, however, the attack has been completely successful.  Here the gas completely routed the French and Algerians, and when 52nd Reserve Division advances, they encounter no resistance.  By 640pm, or less than thirty minutes after their advance had begun, 52nd Reserve Division reaches the hills near Pilkem.  They have advanced almost three kilometres, a stunning gain on the Western Front, and reflects the extent of the German accomplishment.  The use of chlorine gas has completely shattered the Entente line, blowing a hole several kilometres wide between the Yser Canal and Poelcappelle.  Before the Germans are little more than the fleeing remnants of the French and Algerian divisions.  It is a breakthrough that dwarfs those accomplished on two occasions during the First Battle of Ypres.

However, again like those two desperate moments during the first battle, when the outcome hung in the balance, the Germans are unable to fully exploit their advantage.  Here the problem is simply a lack of forces: only a couple of brigades are available to send through the breach in the enemy line.  No further reserves are immediately for two reasons.  First, the impact of chlorine gas has exceeded even the most optimistic expectations of the Germans; quite simply, no one thought its use would open such an enormous gap.  Second, the operation was never intended to be a major offensive designed to win a decisive and strategic victory.  Instead, the attack at Ypres was primarily designed to test the combat utility of chlorine gas and distract the British and French from the flow of German forces from west to east to support the upcoming Gorlice-Tarnow offensive.  Indeed, Falkenhayn had refused the request of the commander of 4th Army for an additional division to be held in reserve near the line; the thinking of the Chief of Staff was that given how the gas attack was dependent on the weather, he could not afford to have a valuable division tied up waiting for the attack to happen, and a significant exploitation of any success was not the point anyway.  It is one of the few occasions during the war when either side will underestimate the potential for an offensive to succeed, and as a result the opportunity to drive to Ypres and inflict a crushing defeat slips away.

Regardless, the surviving Entente forces still find themselves in a desperate struggle to hold back the Germans who are advancing.  Along the Yser Canal the remnants of the French 87th Territorial Division, aided by the Belgians to the north, struggle to prevent the Germans from exploiting their bridgehead at Hen Sas.  East of Langemarck, 3rd Canadian Brigade of 1st Canadian Division, on whose flank the Algerians had formally held the line, bends its left wing back until it runs south towards St. Julien in an effort to prevent the Germans from turned their flank and driving further eastward.  Despite suffering from the gas, the Canadians recover from the initial shock of the attack, and in places are able to recover lost ground.  In the gap, the first reinforcements to arrive are two Canadian battalions, the reserve of 1st Brigade and stationed nearby when the attack began.  They plunge into woods near St. Julien and, massively outnumbered, engage in desperate combat and briefly check the Germans before being forced back.  Other reinforcements have already been ordered to the front, but they are still en route at midnight, and the hole in the Entente line remains, a gaping wound that, to the eyes of French and British commanders, threatens disaster.

The position at Ypres at midnight on April 22nd, 1915, showing the extent of the German breakthrough seized this evening.

- As the date for the German offensive in the Gorlice-Tarnow region approaches, Falkenhayn believes that surprise is vital to the operation's success.  Should the Russians anticipate the German attack, he explains to Conrad today, the operation may fail.