The Storm Scale is a rating system Mark Rosewater uses to rate the chances of a mechanic coming back to Magic. You can see a detailed explanation of the scale on the Wizards website. The key things to know are:
- It only applies to the item being printed in a Standard-legal set.
- It's Mark Rosewater's personal opinion, which others in R&D might not share.
- A low chance doesn't mean no chance. Madness returned while being rated an 8.
Mark also uses the Rabiah Scale for returning to planes, the Venser Scale for returning planeswalkers, and the Beeble Scale for returning creature types, though they all work they same.
A portion of the data behind this site came from the wonderful Storm Scale Database.
The site was last updated on November 12, 2018.