Hot on the heels of their success in Operatsiya Bagration, Soviet forces struck deep towards the Baltic coast, rapidly severing communications between German Army Group North and what little was left of Army Group Center.
By early October 1944, the Soviets were in view of the Baltic Sea, near the port of Memel, definitively cutting off Army Group North from any retreat route through East Prussia.
Despite Guderian's plea for an evacuation by sea and subsequent redeployment in Central Europe where forces were desperately needed to help stabilize an increasingly dicey situation, Hitler stubbornly refused.
Instead, he ordered the 200,000+ German troops to entrench themselves, in the hope of using the Courland Pocket as a springboard for a future offensive.