By New Year’s Day all prisoners were in barracks but the harsh winter, poor sanitation, shortages of food and supplies, and a smallpox outbreak pushed prisoner deaths to a peak of 491 in March. Temperatures dropped to 18 degrees below zero twice over the winter and nearly two feet of snow fell during a single February storm.The spring thaw came with record flooding. On March 15, prisoners retreated to the barracks’ top bunks as waters rose, washing away 2,700 feet of the stockade wall. With the word of General Lee’s surrender in April, the prison camp began to shut down. The last 256 prisoners left on July 11, 1865. Of the 12,147 prisoners held at the camp, 2,961 never returned home.