"It began with a cold, harsh winter," notes Pat Guinan, Missouri's state climatologist with the University of Missouri Extension Commercial Agriculture Program.
Aided by a February blizzard, Columbia, Mo., received 53.4 inches of snow, causing it and many other cities to rank the year among the snowiest on record.
"St. Louis, Columbia and Kansas City all had top 10 snowiest winter seasons, with Columbia falling short of its snowiest winter since 1889 by only 1.5 inches," says Guinan.
As winter thawed, snow turned to rain in southeast Missouri. Major April flooding resulted at the intersection of the Mississippi and Ohio rivers near Cape Girardeau.
"Heavy snow melt set the stage for floods, and rainfall totals in April showed an exceptionally wet month, especially in southeastern Missouri where 15-20 inches were reported in some communities," says Guinan. "Thousands of acres flooded, and we saw near-record to record crests established south of Cape Girardeau to New Orleans."
Cape Girardeau and Poplar Bluff received more than 70 inches of precipitation last year – at least 25 inches above normal. That made 2011 the wettest year ever for Cape Girardeau.
Extreme weather blew into St. Louis with the Good Friday tornado. Hitting Lambert airport in its 21-mile path, the EF-4 tornado was the strongest twister to hit the city in 44 years.
Tornados continued into May, pummeling Joplin in the southwest corner of the state. The EF-5 tornado hit the city head-on, leading to 161 fatalities. It was the seventh deadliest U.S. tornado and the deadliest in more than 60 years.
Major flooding began in May along the Missouri River, hitting northwestern Missouri hard. An unusually wet spring and the melting of deep winter snow in Montana and the Dakotas quickly filled reservoirs. Those reservoirs released record discharge that contributed to major flooding.
Northeast Missouri added to the flooding trend in June. Rivers and streams filled to record levels in Lewis and Clark counties, as areas saw more than 15 inches in a month that typically averages four for the region.
Southern Missouri drought starkly contrasted flooding in a case of feast or famine.
"It was Missouri's hottest July in more than 30 years, and you have to go back to July 1980 to find one that averaged higher temperatures," continues Guinan. "Unrelenting, oppressive temperatures led to heat advisories and impacts on human health, crops and livestock."
Dryness continued into early fall. September and October saw drier conditions, especially across northern and west central Missouri.
Late fall showed a change, with wetter conditions in November and December. The Bootheel averaged more than 18 inches for the two-month period, making it the wettest November-December since 1957.