Why was the landing at Omaha beach so much more diff-ult than us leaders expected?

The landing at Omaha Beach was significantly more difficult than U.S. leaders expected due to a combination of strong German defenses, difficult terrain, and poor weather conditions. The German forces were well-entrenched and heavily fortified, with machine gun nests, artillery, and obstacles that inflicted heavy casualties on the landing troops. Additionally, the rough seas and poor visibility complicated naval bombardments, leading to ineffective support for the assault. These factors contributed to a chaotic and deadly environment that caught U.S. planners off guard.