'Puff' (i) was an Allied air attack on the marshalling yards at Modane in the south-east of German-occupied France on the strategically important route to Turin in north-western Italy (16/17 September 1943).
Undertaken at the request of General Dwight D. Eisenhower, in his capacity as the commander of the US Mediterranean Theater of Operations, the raid involved 340 British aircraft (170 Handley Page Halifax, 127 Short Stirling and 43 Avro Lancaster heavy bombers) of Nos 3, 4, 6 and 8 Groups of Air Chief Marshal Sir Arthur Harris’s RAF Bomber Command, together with five Boeing B-17 Flying Fortress heavy bombers of the US 8th AAF’s 422nd Bombardment Squadron of the 305th Bombardment Group. The marking of the target, situated in a steep valley, was unsuccessful and the bombing was therefore inaccurate. The bombing caused 60 casualties and destroyed 100 houses, and the Allied losses were one Stirling and two Halifax aircraft.
Another bombing attack was delivered on 10/11 November 1943, when 313 Lancaster aircraft of Nos 5 and 8 Groups. The marking of the target area was difficult, was in fact slightly beyond the marshalling yards, but some 200 of the bombers brought back photographic evidence that they had bombed within 1 mile (1.6 km) of the target and caused severe damage. The bombers lost none of their number in this raid.