Merigold's Hailstorm is a very powerful magic spell which produces a hail storm.
It was created by accident and nobody has been able to replicate it as Triss, along with Yennefer, were injured during the Rivian Pogrom and subsequently the original spell they were trying to cast caused a hailstorm accompanied with lightning clouds instead. According to Nimue, the reason no one was able to replicate the spell is because Triss's mouth was cut and she was speaking indistinctly, and some people further claim that Triss' tongue was faltering from fear despite her reputation as courageous. One of the legend's versions states that Yennefer was with Triss on the Rivian Hil and that Triss was not alone, but this did not prove popular in the artist's vision.
- See the GWENT standalone game version card: Merigold's Hailstorm