Debris fallout

A Correlation coefficient scan reveals a significant volume of lofted debris as high as 30,000 ft (5.7 mi; 9.1 km) during a violent tornado

Debris fallout refers to debris lofted into the air by a tornado that falls back to the ground that can persist well after a tornado has lifted. Debris lofted by stronger tornadoes has been known to travel significant distances, upwards of 200 mi (320 km) on rare occasions. Debris fallout events can be detected on radar using dual polarization products, notably correlation coefficient. Most debris in excess of 1 lb (0.45 kg) is not moved a great distance, however lighter objects, especially paper goods, can be absorbed by the tornado's updraft and moved into the storm's forward-flank downdraft where they can be transported further by non-tornadic downdraft winds.

Notable events

• 1915 Great Bend tornado – A cancelled check discovered in Palmyra, Nebraska was traced back to Great Bend, Kansas, a distance of 210 mi (340 km) and, at the time, the greatest distance any debris had been lofted by a tornado.
• 1984 Barneveld tornado – Charles E. Anderson completed the first study focusing on debris fallout on this F5 tornado. His study produced a large survey revealing a trail of paper debris as wide as 23 mi (37 km) at 110 mi (180 km) from Barneveld and a roughly 85 mi (137 km) long path of heavy debris (>1 lb (0.45 kg)).
• 2011 Super Outbreak – A study identified a Facebook page listing over 1700 lost-and-found documents and other light debris from the entire outbreak. Debris was frequently lofted as high as 5.5–6.5 km (3.4–4.0 mi), particularly from the violent (EF4/EF5) tornadoes.
  • 2011 Smithville tornado – A 5 ft (1.5 m) metal sign was found in Russellville, Alabama, having been traced back to Smithville High School around 50 mi (80 km) away.
  • 2011 Hackleburg–Phil Campbell tornado – Over half of the debris in the database originated from this EF5 tornado in Alabama. A windbreaker weighing over 1 lb (0.45 kg) was lofted 107 km (66 mi) from Hackleburg to Elkmont, and a photograph was lofted from Phil Campbell, Alabama to Lenoir City, Tennessee, a distance of 353 km (219 mi) and the furthest any individual piece of debris is known to have been lofted.
• 2011 Joplin tornado – A receipt from a tire repair shop dated the same date as the violent EF5 tornado in Joplin, Missouri was discovered several days later in Royal Center, Indiana, 525 mi (845 km) away. This account is disputed as it was revealed family members from Texas stopped in Joplin for repairs, likely forgetting the receipt on a cooler.
• 2019 Lawrence–Kansas City tornado – A 2020 study focusing on this tornado discovered that lofted debris became visible on radar following the tornado reaching violent intensity. Kansas City International Airport had been under a tornado warning, and 16 minutes after the all-clear was lifted, despite being 75 km (47 mi) from the tornado itself, a ground stop was issued as significant volumes of debris was reported on the runway. An airborne debris signature was evident over the airport up to an hour prior to the first reports of debris.

See also

• Tornado debris signature
• Nuclear fallout
• Rain of animals