The Children's Blizzard

What the settlers did not know — could not know, because the Army Signal Corps chose not issue a Cold Wave warning the previous night — was that a dynamic blizzard was just then sprinting across Montana and northern Colorado. A massive cold air mass had formed around Jan. 8, shifting from Medicine Hat, Alberta, to Qu’Appelle, Saskatchewan. Both places saw violent wind conditions and extreme temperature drops. On Jan. 11, the mass raced full bore across the United States, covering more than 780 miles in 17 hours.

http://www.minnpost.com/minnesota-history/2013/01/125-years-ago-deadly-children-s-blizzard-blasted-minnesota