Storm is fault-tolerant: when workers die, Storm will automatically restart them. If a node dies, the worker will be restarted on another node.
The Storm daemons, Nimbus and the Supervisors, are designed to be stateless and fail-fast. So if they die, they will restart like nothing happened. This means you can kill -9 the Storm daemons without affecting the health of the cluster or your topologies.
Read more about Storm's fault-tolerance on the manual.