“
As might be expected, the overall effectiveness of air attacks along the roads turned on the configuration of the ground. The 9th Bombardment Division put 136 tons of high explosive on St. Vith, which stood in the open with a wealth of bypass routes around it on relatively level ground, and stopped the German traffic not at all. Even when the RAF dropped 1,140 tons in a carpet bombing attack at St. Vith, the road center was out of commission for only a day. Yet a mere 150 tons put on La Roche over a period of two days stopped all major movement in this sector of the Ardennes road net. La Roche, be it noted, lay at the bottom of a gorge with access only through deep defiles.
”
”
Hugh M. Cole (The Ardennes - Battle of the Bulge (World War II from Original Sources))