When a Season or Catalog ends, the information begins to become hidden, by default. The information is never deleted or removed from the system. Instead, the default view hides the data so the List View does not become over-crowded. The 'hide' date is based on the end date for the Season or Catalog.
To view data from a past Season or Catalog, use the 
icon near the top, center of the screen and select the desired Seasons or Catalogs to bring into the list view.
Note: This is also useful when working with a Community Ed department whose Seasons or Catalogs differ from another Community Ed department.