Time Machine Backup Utility makes snap shots too.
They are made and maintained on the Internal Drive.
At the Scheduled Time - TM Backup will attempt to Transfer the Snap Shot to the Designated and Chosen Drive the User ( you ) have assigned.
If TM Backup does NOT See the Attached Drive, it will hold the Snap Shot on the Internal Drive until such time as the Destination Drive is attached.
Should the Drive not be presented before the Next Scheduled Backup - TM Backup will create yet Another Snap Shot and hold that snap shot on the Internal Drive
CCC if used in Manual Mode and " Safety Net " within CCC is configured, it too will make Snaps Shots which and when Run will be Transferred to the Designated External Drive.
It is strongly suggested to Use 1 Designated Drive Solely for the Purposes of TM Backup Utility
It is very strongly suggest to Use a Seperate Drive Solely for the Purposes of Carbon Copy Cloner