The Great Blue Norther of 11/11/11
(November 11, 1911) was the biggest cold snap
in U.S. history. Many cities broke record highs early that afternoon. By nightfall, cities were dealing with single-digit temperatures on the Fahrenheit
scale. This is the only day in many midwest
cities' weather bureau jurisdictions where the record highs and lows were broken for the same day. Blue norther is also known as just norther.
The main cause of such a dramatic cold snap was an extremely strong storm system separating warm, humid air from frigid, arctic air. Dramatic cold snaps tend to occur mostly in the month of November, though they can also come in February or March.
Temperatures in Kansas City
had reached a record high of 76° F
(24 °C) by late morning before the front moved through. As the cold front approached, the winds increased turning from southeast to northwest. By midnight, the temperature had dropped to 11° F
(−11.7 °C), a 65 Fahrenheit degree (35 celsius degree) difference in 14 hours.
, the temperature difference was even more extreme. Springfield was at 80 °F (27 °C) before the cold front moved through. Two hours later, the temperature was at 40 °F (4 °C) with winds blasting out of the northwest at 40 mph (65 km/h). By 7:00 P.M. Central Standard Time
(01:00 UTC 12 November
) the temperature had dropped a further 7 °F (12.6 °C), and by midnight, a record low of 13 °F (−11 °C) was established. It was the first time since records had been kept for Springfield when the record high and record low were broken in the same day. The freak temperature difference was also a record breaker: 67 °F (37 °C) in 10 hours.
Record highs and lows were established on the same day in Oklahoma City as well with a high of 83 °F (28 °C) and low of 17 °F (−8 °C); temperature difference: 66 °F (36 °C). This record still holds to this day.
The front produced severe weather and tornadoes
across the upper Mississippi Valley
, a blizzard in Ohio
, and the windy conditions upon front passage caused a dust storm
. Nine tornadoes were reported in the states of Michigan
, and Wisconsin
. An F4 tornado hit in Janesville, Wisconsin
killing 9 and injuring 50. Within an hour of the tornado, survivors were working in blizzard conditions and near zero temperatures to rescue people trapped in debris
Another notable cold snap
The Great Lakes
area has experienced a number of dramatic cold snaps, albeit none so dramatic as the 11/11/11 cold wave. In the early afternoon hours of February 11
, many cities in the Great Lakes area saw temperatures soar to more than 70 °F (21 °C) for the first time ever in February. South Bend, Indiana
reported a record high of 72 °F (22 °C). By 8:00 P.M. CST (02:00 hrs UTC, 12 November
), temperatures had plummeted to near freezing. The previous record high for February 11
in South Bend was only 46 °F (7 °C), broken by over 26 degrees Fahrenheit (14 degrees Celsius).