Methods of operating a charge trap nonvolatile memory device include operations to erase a first string of nonvolatile memory cells by selectively erasing a first plurality of nonvolatile memory cells in the first string and then selectively erasing a second plurality of nonvolatile memory cells in the first string, which may be interleaved with the first plurality of nonvolatile memory cells. This operation to selectively erase the first plurality of nonvolatile memory cells may include erasing the first plurality of nonvolatile memory cells while simultaneously biasing the second plurality of nonvolatile memory cells in a blocking condition that inhibits erasure of the second plurality of nonvolatile memory cells. The operation to selectively erase the second plurality of nonvolatile memory cells may include erasing the second plurality of nonvolatile memory cells while simultaneously biasing the first plurality of nonvolatile memory cells in a blocking condition that inhibits erasure of the first plurality of nonvolatile memory cells.