I know, but the differences unfortunately are a bit too extreme for such a blanket statement to really work in this case.
(And you have to admit, it's a rather surprising weakness, all things considered: Octavia can handle extreme heat, but not extreme cold.)
...Maybe if Klein were to try to "block" the blizzard with a fire spell, with the resulting flecks of water spraying onto Octavia, or something. Not much of a power-up, granted, but it's something.
Why can she nto handle extreme cold? When has that been established? Why is the state of water, Gas, solid, or liquid an issue with her ability to be empowered by it if she is empowered by H20?
There is no reason to make the asumption you have that it requires liquid state water to empower her, nor that she is particularly vulnerable to cold.