2011 Joplin tornado
The tornado initially touched down just east of the Missouri-Kansas state line near the end of 32nd Street at 5:34 pm CDT (22:34 UTC) and tracked due east, downing a few trees at EF0 intensity. Eyewitnesses and storm chasers reported multiple vortices rotating around the parent circulation in that area. Civil defense sirens sounded in Joplin 20 minutes before the tornado struck in response to a tornado warning issued by the National Weather Service, but many Joplin residents didn't heed them. The tornado strengthened to EF1 intensity as it continued through rural areas towards Joplin, snapping trees and power poles and damaging outbuildings. Widening, the tornado then tracked into the more densely populated southwest corner of the city near the Twin Hills Country Club. It heavily damaged several homes at a subdivision in this area at EF1 to EF2 strength. The tornado continued to strengthen as it ripped through another subdivision just east of Iron Gates Rd. Numerous homes were destroyed at EF2 to EF3 strength at that location, and multiple vehicles were tossed around, some of which were thrown on or rolled into homes.
The now massive wedge tornado then crossed S. Schifferdecker Ave., producing its first area of EF4 damage as several small but well-built commercial buildings were flattened. Consistent EF4 to EF5 damage was noted east of S Schifferdecker Ave and continued through most of southern Joplin. Numerous homes, businesses, and medical buildings were flattened in this area, with concrete walls collapsed and crushed into the foundations. A large steel-reinforced step and floor structure leading to a completely destroyed medical building was "deflected upward several inches and cracked". Steel trusses from some of the buildings were "rolled up like paper", and deformation/twisting of the main support beams was noted. Multiple vehicles were thrown and mangled or wrapped around trees nearby. Several 300-pound concrete parking stops anchored with rebar were torn from a parking lot in this area and were thrown up to 60 yards away. Iowa State University wind engineer Parka Sarkar was able to calculate the force needed to remove the parking stops and found that winds exceeding 200 mph were needed to tear them from the parking lot.
Early-April 1957 tornado outbreak sequence
In all, the Dallas tornado killed 10 and injured at least 200 (some sources say 216) others. Damage was estimated at around $1.5–4 million (1957 USD). The tornado completely destroyed about 131 (some sources say 154) homes, badly damaged 111, and mildly damaged 287. Nearly 600 (some sources list 574) structures and more than 500 homes were damaged, including between nine and 28 permanent apartment buildings that were completely destroyed. Some businesses and schools were also damaged, but the Parkland Memorial Hospital was narrowly spared, as was Dallas Love Field. Another, though officially unconfirmed, tornado in Collin County, north of the city, may have briefly touched down just east of the dissipating Dallas tornado and caused damage.
The Dallas tornado was heavily documented, filmed, and photographed by several eyewitnesses as it passed through residential and commercial areas of Dallas. Visible for much of its path, the tornado, at the time, was the most observed in recorded history: 125 observers produced thousands of photographs and hours of high-quality, 16-mm film measuring in length. The tornado was highly visible due to its slow, forward speed, a lack of precipitation, and its coincidence with ideal, late-afternoon lighting. Occurring shortly before the end of the workday, the tornado passed just west of Downtown Dallas and was seen by many business and factory workers. Many TV studios had time to film the tornado from rooftops.