When the outside temperature is so low that all bodily fluids that leave the body freeze quickly. Therefore when mucus leaks from the nasal passage and freezes it forms a stalactite from the nostrils.
When Harry and Lloyd were driving to Aspen on a skooter without the necessaryprotectiveclothing for Aspens climate, snotsicles formed around their nostrils.
Primarily found in cold climates, the snotcicle occurs when the fluid of a runny nose freezes, creating a sort of icicle. Freequently found in the beard and/or mustache of rugged outdoors men.