The Wild Hunt
During winter storms, Odin leads the Wild Hunt of spirits across the sky.
The Wild Hunt was a spectral procession led by Odin during winter nights, especially around Yule. The dead, including Odin's Einherjar, rode the storm winds. Those caught out might be swept up in the Hunt or receive prophecy.
When the storm winds howl, stay indoors - the Wild Hunt rides.
The Wild Hunt represents the dangerous spiritual power of the winter season.
Various Sources