In wireless sensor networks (WSNs), a large number of sensor nodes are deployed over a large area and long distances and multi-hop communication is required between nodes. So managing numerous wireless sensor nodes directly is very complex, and is not efficient. The management of WSNs must be autonomic self-managed with a minimum of human interference, and robust to changes in network states. To do this, we propose a scalable self-management framework for WSNs called SNOWMAN (SeNsOr netWork MANagement) framework. Our SNOWMAN framework is based on hierarchical management architecture and on the policy-based network management (PBNM) paradigm. SNOWMAN can reduce the costs of managing sensor nodes and of the communication among them using hierarchical clustering architecture. SNOWMAN can also provide administrators with a solution to simplify and automate the management of WSNs using PBNM paradigm.