Blizz Powder is a material added by Thermal Foundation. It can be obtained by processing Blizz Rods, just like Blaze Powder can be obtained by processing Blaze Rods. However, it can also be created by infusing Snowballs with Destabilized Redstone using a Fluid Transposer.
Blizz Powder only has a single use: it is a critical ingredient for creating Cryotheum Dust, and, ultimately, Gelid Cryotheum.