You will see that you have a table #something. So table variables are not stored in memory they are a temp table . It doesn't state anywhere (I can find) in BOL that they are stored in memory.

This has been discussed in other threads and I believe there are articles on MS site that refer to this. When you create a table variable, SQL will create a #table in tempdb but may or may not use it. It all depends on how much data and whether SQL has space for it in memory. It could start of in memory but at any time be transferred to tempdb.