1955 Scottsbluff tornado

In the afternoon hours of June 27, 1955, a violent and well documented multiple-vortex tornado moved through the communities of Henry, Morrill, Scottsbluff and Minatare, all located in the state of Nebraska. The tornado, known informally by the National Weather Service as the Scottsbluff, Nebraska Tornado, was the most well-documented tornado in history at the time of the event. The tornado was one of the first multi-vortex tornadoes to be captured on film and in photographs; over eighty photographs were taken of the tornado along its path.

Meteorological synopsis The tornado was associated with a supercellular storm that tracked over the North Platte Valley at approximately during a period spanning shortly over two hours. "They were associated with a single cumulonimbus cloud which moved down the North Platte Valley at 12-15 kn during a 2-1/2-hr period." At the time of the tornado, the cloud base was above ground level. "The cloud base was about 4000 ft above the ground " All thirteen confirmed tornadoes, including the Scottsbluff tornado, dropped in the southeastern portions of the storm, moving in various directions. "At least 13 different tornado funnels which reached the ground were observed in Nebraska over a 30-mi path and each moved in a different direction "

Tornado summary The first confirmed sighting of the tornado on the ground was from a resident of Henry, who saw the tornado first form as a waterspout west of the town. "The first sign of a tornado in Nebraska on June 27 was observed by a local citizen at Henry, n’ehr. He was looking west toward Wyoming watching a dark cloud moving toward him." The tornado picked up water as it crossed over the North Platte River, forming a visible condensation funnel made of water particles. At this point, the tornado was moving directly to the east, which was confirmed by at least one other observer who saw the tornado form. " permit a complete study as the “waterspout” was moving directly toward the observer the occurrence of the “waterspout”, its size, shape, and location, was verified by another observer." As it hit Henry, the tornado produced minor damage to cottonwood trees.

In an October 1955 Publication of the Monthly Weather Review, meteorologist Edgar L. Van Tassel wrote that "it appeared as though a giant hand had reached down grasping the tree tops and pulled upward until the roots were freed from the soil and then the trees were dropped", noting damage in Henry. "A tornado moved directly over the village of Henry with damage only to cottonwood trees. It appeared as though a giant hand had reached down grasping the tree tops and pulled upward until the roots were freed from the soil and then the trees were dropped." For approximately to the east of Henry, the tornado produced no discernible ground damage, before deroofing a farmhouse as it moved into a valley. "Over open fields to the east of Henry there was no sign of ground damage for 3 miles tornado moved over a hill about 50 feet in height into the valley, passing directly over a small farm house." Two people were in the house, both of whom survived the event. "Two occupants reported that the house though it was twisted from its foundation it remained upright."

Shortly after impacting the farmhouse, it was noted that the tornado's damage path "skipped" and was discontinuous. Seven visible funnel clouds were observed as the tornado was in this phase, although the tornado itself lost the condensation funnel it had formed when moving over the river earlier along its path. "In several instances along the tornado path there seemed to be a skip in the destruction on the downward side of a hill that the tornado had passed over." The tornado curved to the southeast and then abruptly changed its direction, moving directly east. "The storm cell moved south-southeast for approximately 6 miles and then curved and moved directly east for 7 miles." The tornado was observed firmly on the ground west of Mitchell, where it stayed on the ground until dissipating later. "From 2 miles south of Mitchell, Nebr., a funnel cloud maintained contact with the ground until cloud dissipation 8 miles east of Scottsbluff."

Prior to reaching the ground, uncertainty existed around whether the tornado was on the ground due to the lack of a continuous path, although the path past Mitchell was confirmed by residents who observed and documented the tornado as it moved by. The tornado exhibited abrupt changes in direction as it neared the town of Scottsbluff, where it turned to the south and curved east several times. "From south of Mitchell the tornado moved due east for 7 miles then turned at, right, to the south for 1 mile, then cast for 2 miles, thcn south 1 mile " It tracked over rural areas for the majority of its life, although it directly hit one housing project containing seventeen units; both fatalities recorded from the tornado took place at this location. One death took place in a vehicle and the other occurred when a large vehicle landed on a boy as he was taking shelter in a ditch. "A boy was killed by a truck being hurled upon him as he took refuge in a ditch, and a lady was killed when the car in which she was riding was caught in the tornado funnel."

The tornado destroyed a total of 146 structures and injured 40 others, "Forty persons were injured and 146 buildings were destroyed or damaged." along a path spanning around two hours on the ground. Damage from the tornado received an F4 rating on the Fujita scale.

Documentation At the time of the event, the tornado was the most well-documented in history. "This tornado situation, at the time, was un-questionably the most photographed in history " Over 90 black-and-white photos and ten videos were taken by witnesses along the tornado's path. "10 movies, 35 Kodachrome slides, over 90 black and white photos, and many damage photos " Using photographs of the tornado, meteorologists were able to calculate precise measurements of the tornado's height and width. " it was possible to locate the exact spot from which many pictures were taken and to measure the distance from that point to the path of the tornado." The tornado was also visible on modified AN/APS-2 radars that were used by the Weather Bureau Office (WBO), where eight photos were taken of the storm's structure. "The radar was a 10-cm. APS-2F with a 72-in. antenna eight similar pictures were obtained as the tornado moved from 18 miles " A defined hook echo is visible in the radar photographs taken by the WBO; the tornado passed less than to the south of the radar site, cutting off power to the site and preventing further radar observations as it moved to the southeast. "The tornado passed one-half mile south of the radar cutting off all power so no view of the dissipation of the tornado cloud was observed on the radar."

Cycloidal marks Northeast of Scottsbluff, near the end of the tornado's path, cycloidal debris marks were documented in aerial shots after the event. "Figures 8 and 9 are aerial photographs of some unusual markings in a cultivated field northeast of Scottsbluff that were caused by the tornado." At the time, cycloidal marks were an unknown phenomenon, and the marks left by the Scottsbluff tornado were the subject of a detailed study. "There could be considerable speculation as to how the tornado produced these marks." The cycloidal marks, in conjunction with radar, were used to determine the forward speed of the tornado and showed the tornado's abrupt movements. "The forward speed of the tornado cloud cell as determined by the radar gave an estimated forward speed of the tornado of 12 m.p.h." "The stairstep line of the tornado path near Scottsbluff as shown in figure 1 is an indication of abrupt direct'ion changes."

Gallery

1955 Scottsbluff tornado

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