In a (marginally) cursed world rains of blood are an occasional occurrence. The water in the clouds is magically transmuted into blood at the point it starts to coalesce into droplets (no need to worry about how to evaporate blood), and will transform back into water after a short while on the ground (so don't worry about the effects on the ecosystem).
In low temperatures I'm unsure of whether such magically transmuted water will form snowflakes. To the best of my knowledge the water in moist, low temperature air has a short liquid phase before it freezes onto the snowflake proper, but I don't know if magically transmuting it at this point would lead to blood snow or blood hail, as I don't know what the impurities in the water will do to the formation.
For reference the freezing point of this magical blood is ~-2 degrees C.
In freezing temperatures should I expect flurries of blood or hailstorms of blood?