TempDB Full

Hi

Today Morning @ 11.40 AM. Got error like ,

Message
The transaction log for database 'tempdb' is full. To find out why space in the log cannot be reused, see the log_reuse_wait_desc column in sys.databases

Then immediately we expanded the space issue got resolved. It is Prod server.

Now i want to check  @2.30 PM why tempdb got full.

How to check because after 12.10 PM not alerts. Currently server is working fine. But i want to submit RooT Cause Analysis to management.