iTunes File Sharing can be used to backup your tracks and transfer these tracks to your computer or another device.
If you use Ski Tracks -> Settings -> Tools -> Backup All Tracks then a backup folder will be created on your device that is accessible through iTunes. This backup folder is also transferred to iCloud if left on the phone.
If you recover your phone through iCloud check whether the backup folder exists, copy this folder to your computer and then copy the .skiz files to the Ski Tracks Document panel. When Ski Tracks starts or activates it will automatically import all .skiz files found.
Copy the backup folder to your computer for your safety. i.e. Drag the backup folder to your desktop.