May 27-29, 1947 Snowstorm

One of the most unusual weather events in Iowa history occurred as an intense low pressure system moved northeast across Missouri and into the Great Lakes region, passing over the far southeastern corner of Iowa. Meanwhile an unseasonably cold area of high pressure spread down the northern plains bringing record breaking cold temperatures to much of the region. A heavy snow storm tracked along the northwestern side of the low across eastern Wyoming and Colorado, Nebraska, Iowa, Wisconsin, and into northern Michigan from May 27-29 producing unprecedented snowfalls for so late in the spring. In Iowa the storm struck on the 28th with most precipitation in the south coming in the form of thunderstorms and rain, sometimes mixed with sleet and snow, while across about the northern half of the state the precipitation fell almost entirely as snow. In Iowa, measurable snow was recorded at most locations north of a line from Council Bluffs to Dubuque with reported accumulations including an incredible 10.0 inches at Le Mars, 8.0 inches at Cherokee, 7.5 inches at Waukon, 6.0 inches at Alton and Hawarden, 5.0 inches at Cushing, Iowa Falls, Milford, and Northwood, 4.5 inches at Mason City, 2.0 inches at Waterloo, and a trace at many locations including Des Moines. In Nebraska several locations received 10 to 12 inches of snow and in Wisconsin 8 to 10 inches fell in a narrow band from Gays Mills to Green Bay. To put into perspective how unusual this event was, no snow has ever been recorded anywhere in Iowa at a later date in the spring. The total of 10.0 inches at Le Mars was the highest snow accumulation on record in Iowa at any time in the month of May until it was bested by the storm of May 1-3, 2013. A series of heavy rains in the following several weeks combined with the snow-melt from this storm to produce historic flooding across many parts of Iowa in June of 1947.

May 27-29_1947 Snow Storm