Tornadoes - June 2010
NCDC added Alaska climate divisions to its nClimDiv dataset on Friday, March 6, 2015, coincident with the release of the February 2015 monthly monitoring report. For more information on this data, please visit the Alaska Climate Divisions FAQ.
The annual increase in number of severe thunderstorms and tornadoes continued into June with an active pattern across the northcentral United States. There were 387 preliminary tornado reports during June, marking the highest monthly tornado count of 2010 to–date. The most active regions of the country were the central and northern Plains, the Midwest, and Great Lakes region where ten fatalities were reported in five tornadoes. According to the Midwest Regional Climate Center the region had more than 2,000 severe weather reports during June, with only three days not having severe weather. Minnesota had 67 preliminary tornado reports during the month. This shatters the previous June tornado record, which occurred in 2005 when 35 tornadoes affected the state. The June tornado count for the United States as a whole was much above the long–term average, and if the preliminary reports are confirmed will mark the second busiest June since 1950, behind June 1992 (401 tornadoes). There were two major tornado outbreaks which occurred during the month with over 60 preliminary tornado reports each.
The first major outbreak occurred on June 5th, when there were 64 preliminary tornado reports across portions of the Midwest, stretching from Iowa into western Pennsylvania. A low pressure system with an associated cold front strengthened as it moved across the southern Great Lakes. Moist and unstable air ahead of the cold front primed the atmosphere for severe thunderstorms. The strongest tornado of the outbreak occurred in northwest Ohio killing six people in the small town of Millbury, just before midnight. The EF–4 rated tornado brought winds of 170–175 mph (274–282 km/hr) with a path width of up to 400 yards (366 meters). The tornado remained on the ground for 8–10 miles (13–16 km). The Millbury tornado was the second most deadly tornado of 2010 to date. Also associated with the outbreak were three non-fatal EF–3 tornadoes near Grissom Air Force Base in Indiana; Saint Anne, Illinois; and Livingston County, Illinois. Please see the Global Hazards Storm Report for additional information on this tornado outbreak.
North Dakota and Minnesota Radar 17 June
The second major outbreak of June occurred on the 17th in the upper Midwest. A strong low pressure system moved northward through the region, bringing severe weather. There were 77 preliminary tornado reports across North Dakota, Minnesota, and Iowa. Three EF–4 tornadoes occurred in Minnesota and one occurred in North Dakota. The occurrence of numerous strong tornadoes in this region is rare. According to information from the National Weater Service Offices in Grand Forks, North Dakota and the Twin Cities, Minnesota the last EF–4 or stronger tornado in Minnesota occurred on July 25th 2000, and the outbreak marked the most EF–4s or stronger in any single event in Minnesota since April 1967. For the entire nation, this was the first time that an outbreak produced four EF–4s since the “Super Tuesday” outbreak of February 2008. The outbreak was directly related to three fatalities, which is the highest number of tornado related fatalities for a single day in Minnesota since July 5th 1978 when there were four. One fatality was reported with an EF–4 near Holmes, North Dakota. Please see the Global Hazards Storm Report for additional information on this tornado outbreak.