Maelstrom

While normally weather has no effect on magic when already focused in spells, storms of sufficent size or strength can cause the weavings of spells to unravel or fray by virtue of the amount of anima moving around in the air. When this occurs it is called a Maelstrom. While no more dangerous than a regular storm on the surface they render any magic that reaches more than a short distance to fail if not backfire. Teleportation and and such break down, and even simple spells can become diffcult to control.
Anything as simple as a thunderstorm can become a maelstrom if the conditions are right. But more severe weather conditions are all but certain to generate malestroms.
Maelstroms occur more easily in areas of high Anima concentration, and are thusly more common. So while rare in low anima locations a suffecently powerful storm could cause a maelstrom anywhere.

Manifestation

One can distinguish a malestrom from a regular storm by the energy discharged when waves of anima crash into each other and violently release energy in the form of a sharp piercing whine sound followed by an explosion and snap of light. The more anima in the air the more blue the light is.
These energy discharges release large amounts of radiation into the environment, so it is generally advised not to go outside until the day after the malestrom is over.

Magic

Magic use in maelstroms is not reccomended as the anima in the environment has a tendancy to warp magic in unintended ways. Even a spell that suffuses the caster's body exclusively could have devistating side effects despite not interacting with or traveling through the environment at all.

Type

Metaphysical, Elemental