This is the boring part. A tornado, as you may have learned from your parents, is what happens when mighty Thor's laundry hits the spin cycle. It is made mainly of wind and cows, although rednecks have historically accounted for a seemingly insignificant (but actually pretty significant) 2.3% of tornado biomass. When any given tornado has a redneck biomass index (RBI) of 1.2% or higher, it tends to migrate north because of Southerner shame, up north where it is cold and sexy Canadians party all night long.
Canada is where glaciers are born, and so if a tornado happens across a glacier nest and the mother glacier is gone, the rednecks (having developed a taste for pina coladas and margaritas while partying it up with the Canucks) will exert a subtle psychological force upon the tornado, tending it to pick up the large hunks of ice which the rednecks, confused and drunk as they are, naturally assume will be ground and broken up into alcohol-useful slush by the madly flailing hooves of the cows. They are wrong.
Glaciernadoes in the Bible
None. The bible is not cool enough to have any glaciernadoes.
Glaciernadoes in Prehistory
The theory that a comet systematically broke itself into pieces and assassinated all the dinosaurs, while largely accurate, misses the fact that the chunks of comet ice were assisted by a grudge-bearing glaciernado which stationed itself roughly 35 miles northeast of what is today known as Grumbler's Catapult, New Texas.
Glaciernadoes in Europe
Ha ha, ha. No.
The mythical Siberian snow god Thajrtunkyantka (literally, It's Spitting Snow All Over the Village Again, Dammit) is thought to have been an ignorant superstitious interpretation of a glaciernado. The legend persists to this day in some form or another, with the widespread popularity of Thajrtunkyantka Cola (and Diet Vanilla Blueberry Thajrtunkyantka Cola) and Siberia's largest high school, Gjreyvink Polytechnical, which utilizes Thajrtunkyantka as a mascot.
Safety in a Glaciernado
First off, coating oneself in hot sauce is crucial, as hot sauce melts ice. Secondly, a beanie hat will combat the windiness. Other than that, a shotgun is optional but recommended, because most of those rednecks will be upset about their mistake regarding crushed ice for spirituous beverages. Watch out for Confederate flags, as you can become entangled in one and lose your sense of direction.