Map 9. V Corps barrage map, Cambrai, 20 November 1917. At Cambrai the BEF fired a lifting barrage that moved straight from target to target instead of sweeping all the ground in between lines, as a creeping barrage (MAP 1) did. The smoke barrages shown here were weather-dependent, but the weather was favorable on 20 November and they were fired. However, while they were effective for their duration, that duration had been miscalculated, and German anti-tank fire became effective.
Source: OH 1917, vol. 3.