The great bombardment at Ypres began, with the British guns one to every six yards of front, more than at Arras earlier in the year and almost twice as many that the 4th Army had on the Somme a year previous. For the arriving Australian artillery they would endure conditions much more severe than on the Somme, where due to German air parity and being positioned on the plains overlooked by the German spotters, the positions in the rear including the gun batteries were targeted much more heavily causing many casualties at such a rate that it was feared reinforcements would have to be raised on a scale similar to the infantry.