How to effectively determine the cause of L2 loops

Hello,
We have a vast L2 network, and I was wondering the best way to quickly determine what device/port is causing loops. We use Juniper EX series devices, with all variations of stp disabled and storm control enabled. Generally, when things start storming we clear the mac table, disable ports, and eventually if it isn't fixed we get Wireshark captures. Could anyone give me some strategies of a quicker/more effective ways to troubleshoot loops faster?