The link below allows you to download all of your campaign data in a CSV document. You can use this to store a backup of the data for your campaign.
Note that it is not possible import this data back into the website. (and likely it never will be)

Download CSV Data

Descent: Journeys in the Dark is ™ and © Fantasy Flight Publishing, Inc.
All rights reserved. Used with permission.
Descent Campaign Tracker is created and maintained by Steven Yackel. (BGG: spazard1)  Please report any bugs you encounter. 
Descent Campaign Tracker has been hosted by Steven Yackel until 2014 for free. Since 2014 BGG: ionas / hosts it for free.