In a comment, aparente001 suggested:
Subzero. Frigid. Super-freezing. Intensely freezing. Frozen solid. Freezing past the point of no return. Below zero freezing. Bone-chilling cold.
In a comment, aparente001 suggested:
Subzero. Frigid. Super-freezing. Intensely freezing. Frozen solid. Freezing past the point of no return. Below zero freezing. Bone-chilling cold.