SnowStorm

SnowStorm is a het relationship between Caitlin Snow and Ronnie Raymond on CW series The Flash.

Canon
Caitlin and Ronnie meet in StarLabs, where they both work and begin an opposites attract romance, as Caitlin relays it to Barry. Ronnie is a very sweet, kind, outgoing and adventurous person, while Caitlin is the equally sweet and kind, but of a more quiet and cautious nature. Once Cisco discovers Ronnie is still alive and the team realises he's Firestorm (with Professor Stein), Caitlin and Ronnie reunite and the Team saves Firestorm.

Ronnie asks Caitlin to leave Central City with him and start their life together anew, but Caitlin wants to remain in Central City to help people with Team Flash. Ronnie understands and leaves for a while with Stein to figure out their lives together as Firestorm. Ronnie returns to help out the team later on and re-proposes to Caitlin, who accepts. Professor Stein officiates their wedding and theyr are happily married, but when Ronnie helps Barry close the portal to other dimensions, he is killed (supposedly).

Caitlin is devastated at losing him again, but is willing to put the team back together with Barry and Cisco, to continue helping people in need.

Earth-2
When Barry and Cisco pay Earth-2 a visit, they come across Caitlin and Ronnie's doppelgängers, who are evil – Killer Frost and Deathstorm. Although evil, the two still display affinity for one another and Killer Frost is livid when Deathstorm is killed.