Originally Posted by
SASless
The great planning somehow overlooked what kind of terrain lay behind the beaches in Normandy and did not appreciate the effect the Hedgerows would provide the defenders.
It wasn't overlooked, but it was very much a secondary concern. The primary issue was making the landings on beaches that were less heavily defended so that the initial landings would be successful. If the initial landings didn't succeed, what laid behind the beaches wouldn't matter.
That's why they didn't go to Calais or to a channel port - those were
much heavier defended than the Normandy beaches.
Lots went wrong at Omaha - perhaps the biggest being that the DD tanks were offloaded too far from shore and were swamped by the heavy seas. Something like 90% of the DD tanks at Omaha sank. Had even half of them made it, their firepower would have made a big difference.