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1967 Chicago blizzard

Snowstorm in the Midwest United States

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  • 9 chapters

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Chronology

On Tuesday January 24, the maximum temperature was 65 °F (18 °C) but began to fall the next day with the passage of a marked cold front. In fact, the front brought arctic air from a strong 1032 mb high pressure center over the southern Canadian Prairies. By the morning of January 25, the mercury had dropped to 31 degrees F.

On the other hand, an upper-level baroclinic trough, coming from the Rockies, developed a low pressure system at the surface near the Texas Panhandle. At midnight Thursday, January 26, the low moved to Oklahoma while strengthening. During the day, the elevated trough and surface low crossed the Mississippi Valley, reaching South-central Indiana before midnight on January 27 and deepening to 997 mb.

Dew points of 50 to 60 °F (10 to 16 °C), or more, in the warm sector of the surface low brought significant humidity from the Gulf of Mexico while the high pressure moved to the Lake Superior, keeping cold and dry air over the Great Lakes. The strong pressure gradient between the latter and the low pressure center caused strong winds over Lake Michigan, causing widespread blowing snow while heavy snowfall affected the Chicago area.

On January 27, the low occluded. Its central pressure reached 990 mb while passing over Lake Erie and Southern Ontario, Canada. Snow stopped in the evening in Chicago and strong winds moved north-northwest out of the region.

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