A storage system includes a nonvolatile memory device and a controller. The nonvolatile memory device includes first and second memory blocks and stores data corresponding to first and second volumes. The controller performs a snapshot function on the data corresponding to the first and second volumes and determines data to be stored in the first and second memory blocks based on parameters for generating snapshots of the first and second volumes. The controller stores data corresponding to a snapshot deleted at a first time point in the first memory block, stores data corresponding to a snapshot deleted at a second time point in the second memory block, adds the first memory block to a victim block list after the first time point, and adds the second memory block to the victim block list after the second time point.