From April 2–3, 1956, a large, deadly tornado outbreak affected the Great Plains, parts of the South, and the upper Midwest in the contiguous United States, especially the Great Lakes region. The outbreak produced at least 55 tornadoes, including an F5 that devastated the Grand Rapids metropolitan area in the U.S. state of Michigan on April 3. It was one of three tornadoes to move across southwest Lower Michigan on that day. A fourth tornado struck north of the Manistee area, in the northern part of the peninsula. The Hudsonville–Standale tornado killed 17 and injured 333. It remains the fourth deadliest tornado on record in Michigan and is the most recent F5 on record there. Several other deadly, intense, long-tracked tornadoes also occurred during the outbreak. In addition to the fatalities in Kansas, Oklahoma, Michigan and Berlin, Wisconsin, three people were killed in Tennessee, one person in Kentucky and two more people in Wisconsin. In total, 39 were killed during the entire event.
Background Tuesday, April 3, 1956, was a warm and humid day across most of the Midwestern U.S., the Great Lakes and the Ohio Valley. Temperatures in the areas affected by the worst of the outbreak were well into the 70s °F, approaching in Michigan, with anomalously high dew points—the latter exceeding near the shoreline of Lake Michigan. A potent low-pressure area accompanied an intense mid-latitude cyclone with a pronounced dry line located near the western Great Lakes. An attendant warm front extended eastward over Wisconsin, a vigorous cold front southward through Illinois. In tandem with the advancing trough, a strong jet stream with winds up to extended over Little Rock, Arkansas, and impinged on the Upper Midwest. Prior to the arrival of the storms in the region, schools had closed earlier than usual due to the threat of severe weather. By late afternoon, the cold front crossed over the western Great Lakes including Lake Michigan.Multiple sources:
Outbreak statistics + Daily statistics of tornadoes during the tornado outbreak of April 2–3, 1956 DateTotalF-scale ratingDeathsInjuriesDamage FU F0 F1 F2 F3 F4 F5 April 22003473307144≥ April 3353121855132646 Total553462588139790≥
Confirmed tornadoes
Prior to 1990, there is a likely undercount of tornadoes, particularly E/F0–1, with reports of weaker tornadoes becoming more common as population increased. A sharp increase in the annual average E/F0–1 count by approximately 200 tornadoes was noted upon the implementation of NEXRAD system of Doppler weather radar in 1990–1991. 1974 marked the first year where significant tornado (E/F2+) counts became homogeneous with contemporary values, attributed to the consistent implementation of Fujita scale assessments. Numerous discrepancies on the details of tornadoes in this outbreak exist between sources. The total count of tornadoes and ratings differs from various agencies accordingly. The list below documents information from the most contemporary official sources alongside assessments from tornado historian Thomas P. Grazulis. In addition to confirmed tornadoes, a funnel cloud near Jenera, Ohio, was officially but incorrectly listed as a tornado.
+ Color/symbol key Color / symbol Description † Data from Grazulis 1990/1993/2001b ¶ Data from a local National Weather Service office ※ Data from the 1956 Climatological Data National Summary publication ‡ Data from the NCEI database ♯ Maximum width of tornado ± Tornado was rated below F2 intensity by Grazulis but a specific rating is unavailable.