Question: On what date did the tornado occur that destroyed Plaza Towers Elementary School?

Context articles: 2013 Moore tornado
Charleston Community Unit School District 1
Burbank School District 111
Travis Unified School District
1968 Tracy tornado
Jasper County Community Unit School District 1
North Boone Community Unit School District 200
Zion Elementary School District 6
Braintree Public Schools
Plaza Towers Elementary School

On the afternoon of May 20, 2013, an intense and destructive EF5 tornado struck Moore, Oklahoma, and adjacent areas, with peak winds estimated at 210 mph , killing 24 people (plus one indirect fatality) and injuring 377 others.
 The tornado was part of a larger weather system that had produced several other tornadoes across the Great Plains over the previous two days, including five that struck portions of Central Oklahoma the day prior on May 19.
Charleston Community Unit School District 1 is a unified school district based in Charleston, the county seat of Coles County, Illinois; it was created through the consolidation of the charter school district it was formed from and over sixty-seven other school districts in the area.
 Charleston Community Unit School District 1 is a conglomerate of six schools, with all but one located in Charleston itself: four elementary schools, one middle school, and one high school form the makeup of the district.
 Education begins at a prekindergarten level, and those living in the Charleston area attend Mark Twain Elementary School, which prepares early youth for schooling by taking them through prekindergarten and kindergarten under the supervision of principal Terry Diss.
 Students who live in the far east reaches of Coles County may attend Ashmore Elementary School, which is based in a northeasterly village by the same name; Ashmore's distance from the other schools permits it to educate a larger range of students for the sake of efficiency.
 The school educates students from kindergarten through grade four, and also runs a prekindergarten program.
 Ashmore is also governed by Terry Diss.
 Students who graduate from Mark Twain move onwards to Carl Sandburg Elementary School, which educates those in grades one, two, and three under principal Chad Burgett.
 At Jefferson Elementary School in Charleston, the student bodies from both Carl Sandburg Elementary School and Ashmore Elementary School are consolidated.
 Students from grades four through six are taught in the facility under the supervision of principal Deborah Poffinbarger.
 District students graduating from Jefferson are moved to Charleston Middle School, where they are taught as seventh and eighth graders; the school principal here is Sandy Wilson.
 The last branch of education that Charleston's school district can provide is the education of adolescents in the grades nine through twelve at Charleston High School, which is run by principal Trevor Doughty.
 The superintendent of the schools in the district as of the 2007-08 school year was Dr. William Hill, although is considered as an interim;lastly, the mascots of the district and its middle and high schools are the Trojans, while the mascot of Jefferson Elementary School is the bulldog.
Burbank School District 111 is an elementary school district located in Burbank, a Chicago suburb just south of Chicago Midway International Airport in Cook County, Illinois.
 There are seven elementary schools in District 111.
 They are all kindergarten through sixth grade and located within the city of Burbank.
 The elementary schools are: Luther Burbank Elementary School under direction of principal Robert Mocek, principal Marian Stockhausen's Richard Byrd Elementary School, Jacqueline Kennedy Elementary School under direction of principal Charles Roza, principal Mark Antkiewicz's Rosa Maddock Elementary School, principal Patricia Donaghue's Frances McCord Elementary School, principal Mary Anne Sheehan's Edward J. Tobin Elementary School, which was reopened in 2007 after being rebuilt, and principal Mary Rein's Harry Fry Elementary School, which closed after the 2003-2004 school year and reopened during the 2009-2010 school year.
 Graduates from all these elementary schools move on to Liberty Junior High School, which is under direction of principal Jim Martin.
 The district superintendent is Carol Kunst.
Travis Unified School District is a Unified School District located in Fairfield.
 It serves students from Fairfield, Vacaville and Travis A.F.B. in a total of 9 schools throughout its district.
 These schools include 1 high school, 1 alternative high school, 1 middle school, 2 alternative middle schools and 5 elementary schools.
 The elementary schools are Scandia Elementary School, Travis Elementary School, Center Elementary School, Cambridge Elementary School, and Foxboro Elementary School.
 The middle schools include 2 alternative schools in Travis Independent Study School and Travis Community Day School as well as a public middle school in Golden West Middle School.
 The high schools include 1 alternative high school in Travis Education Center (TEC) and 1 public high school in Vanden High School.
The 1968 Tracy tornado.
 was an F5 tornado that struck Tracy, Minnesota on June 13, 1968 at around 7 o'clock.
 The tornado killed nine people and injured 125 others.
 The wind speeds of the tornado reached over 300 mph as it tracked 9 mi through Murray, Lyon and Redwood counties in southwestern Minnesota.
 It is one of only two official F5 tornadoes that have occurred in Minnesota, although several other tornadoes that occurred before 1950 are estimated to have been F5 strength.
 The tornado destroyed 111 homes, caused major damage to 76, and caused minor damage to 114.
 Five businesses were destroyed and 15 others were damaged.
 Some homes in town only had their foundations left behind.
 A few farms outside of town were swept completely away, and extensive ground scouring occurred.
 An elementary school and 106 automobiles were destroyed, and a heavy boxcar was thrown more than a block by the storm.
 Two other boxcars were thrown 300 yards, and a steel I-beam was carried for two miles on a piece of roof.
 Hard rains and hail were also reported.
 A total of five tornadoes hit Minnesota on June 13, 1968, most ranking as an F0.
Jasper County Community Unit School District 1 is a unified school district based in Jasper County's county seat of Newton, Illinois; it is the only school district in the county and is, consequently, the main educational body in all of Jasper County, although it serves portions of Effingham County and Cumberland County as well.
 This school district is composed of six schools in total; four elementary schools, one junior high school, and one high school.
 There is also a prekindergarten program run at the high school of the district should parents wish to enroll their children early.
 Willow Hill Elementary School, which is located in the village of its namesake, serves only kindergarteners; its proximity to the county seat and central position in the county allows its students to dawn from all parts of the county and still have easy access to the elementary school they will attend.
 The principal of Willow Hill is Dave Parker.
 Grove Elementary School is located in Island Grove, Illinois, the highest point of elevation in the county.
 Grove Elementary School educates students from kindergarten to grade six, and it runs a prekindergarten program as well.
 Craig Carr is the principal of this school.
 Ste. Marie Elementary School is located in the southern Jasper County village of Ste. Marie, and serves students in grades one through six.
 The principal of Ste. Marie is David Parker, the principal of Willow Hill Elementary School.
 Newton Elementary School is located in the county seat of Newton, and serves most of west Jasper County's first through sixth graders under principal Travis Wyatt.
 The latter three elementary schools feed into Jasper County Junior High School and are taught in the facility during seventh and eighth grade while being supervised by Newton Elementary School principal Travis Wyatt before graduating into Newton Community High School.
 Students in grades nine through twelve spend their last leg of precollegiate education at this school; their principal is Ruth Kerner.
 The district superintendent is Ron Alburtus, and the district's mascot is the eagle.
North Boone Community Unit School District 200 is a unified school district based in the central region of the county of its namesake, Boone County; more specifically, in the village of Poplar Grove, Illinois.
 Five of the six schools in the district are located here, with the other being eastwards in the village of Capron.
 The community unit school district is composed of, as previously mentioned, six schools: there are three elementary schools, two middle schools, and one high school.
 Manchester Elementary School, which serves the grades K-4 alongside Poplar Grove Elementary School, is governed by Principal Kristi Crawford; the principal of Poplar Grove Elementary School is Sharon Olds.
 Capron Elementary School, the only school in the district located in a village other than Poplar Grove, serves not only the grades K-4, but also includes a prekindergarten program.
 The current principal is Matt Klett.
 All students who graduate from one of the district elementary schools will consolidate at the fifth grade in one school, called North Boone Upper Elementary School, whose principal is Mike Greenlee;all students move on to North Boone Middle School, headed by Jeremiah Auble, which educates those in grades seven and eight.
 The last leg of education this district can provide is to those from grade nine to grade twelve; the facility is called North Boone High School, whose principal is named Jacob Hubert.
 The current superintendent is Steven Baule.
 The mascot of the district high school is the Viking.
Zion Elementary School District 6 is an Illinois school district serving Zion, Lake County.
 The school district governs seven schools.
 Lakeview School is responsible for prekindergarten children, housing also the district's administrative offices.
 Beulah Park Elementary School, East Elementary School, Elmwood Elementary School, Shiloh Park Elementary School and West Elementary School serve students between kindergarten and sixth grade.
 Zion Elementary School District 6's sole middle school, Zion Central Middle School, serves the seventh and eighth grades.
The Braintree Public School District, located in Braintree, Massachusetts, includes Hollis Elementary School, Donald Ross Elementary School, Archie T. Morrison Elementary School, Liberty Elementary School, Mary E. Flaherty Elementary School (formerly Lakeside Elementary School), Highlands Elementary School, East Middle School, South Middle School, and Braintree High School.
 Monatiquot Elementary School is now the Monatiquot School Kindergarten Center for full-day kindergarten students in Braintree.
Plaza Towers Elementary School is a public elementary school in Moore, Oklahoma, in the Oklahoma City metropolitan area.
 It is a part of Moore Public Schools.
 Plaza Towers is located in southwest Moore within a neighborhood of the same name.
 The school's mascot is the panther, named "Paws".
 The school's current building opened in 2014 after the previous facility was destroyed by the 2013 Moore tornado; seven students at the school died as a result of the tornado's impact.