Storm of Memories

• WOTC Official Reminder Textofficial rules
  Storm — When you cast this spell, copy it for each spell cast before it this turn. You may choose new targets for the copies.

• WWizards of the Coast2025-10-02
  Official Ruling
  The copies are put directly onto the stack. They aren't cast and won't be counted by other spells with storm cast later in the turn.
• WWizards of the Coast2025-10-02
  Official Ruling
  The triggered ability that creates the copies can itself be countered by anything that can counter a triggered ability. If it is countered, no copies will be put onto the stack.
• WWizards of the Coast2025-10-02
  Official Ruling
  Spells cast from zones other than a player's hand and spells that were countered or otherwise failed to resolve are counted by the storm ability.
• WWizards of the Coast2025-10-02
  Official Ruling
  A copy of a spell can be countered like any other spell, but it must be countered individually. Countering a spell with storm won't affect the copies.
• WWizards of the Coast2025-10-02
  Official Ruling
  The instants or sorceries cast using copies of Storm of Memories go on the stack as each copy of Storm of Memories resolves, and those spells will each resolve before more copies of Storm of Memories resolve.

Rulings via Scryfall