NWS Survey Ranks St. Louis Tornado That Hit Lambert Field an EF-4 (4/22/2011)


The preliminary findings from the NWS storm survey team from St. Louis is in. This was a long track tornado that hit Maryland Heights, Bridgeton, St. Ann, Edmundson, Lambert St. Louis International Airport, Berkeley, and Ferguson. The tornado continued over the Mississippi River to just north of Granite City, Illinois. Here is a picture of the path the tornado took.

This tornado caused EF-4 damage in Bridgeton with EF-2 damage near Lambert/St. Louis International Airport. If you haven’t read the parent blog post of this tornado, I would encourage you to do so. It’s called: Another Tornado Warning for St. Louis, Missouri; Major Damage at Lambert Airport.

Here is the write up that the St. Louis NWS office did on this tornado.

During the evening of Friday April 22, an intense supercell thunderstorm produced a long-track tornado which tore a path of destruction from west to east across the St. Louis Metropolitan Area. The tornado reached a maximum intensity of EF4 on the Enhanced Fujita Scale as it tracked through the community of Bridgeton, just west of Lambert St. Louis International Airport. The total path length was 22 miles, with a width of up to 0.4 miles.

The tornado initially touched down along the northern edge of Creve Coeur Lake at approximately 755 pm. It tracked nearly due east at about 40 mph, and intensified as it entered Maryland Heights. There it produced up to EF3 damage to many homes and businesses with a damage swath of 200 to 400 yards wide. Damage continued eastward in an unbroken track, crossing I-270 about 1 mile south of I-70. The tornado reached peak intensity of EF4 as it devastated the community of Bridgton along Old St. Charles Rock Road. From there the tornado paralleled Interstate 70 through the community of St. Ann, then took aim directly on Lambert St. Louis International Airport. Many of the large windows in the main terminal building were blown out or damaged by flying debris and a large section of roof was peeled from Concourse C. Although the vast majority of people were evacuated to lower levels and to interior rooms before the tornado hit, 5 people were treated and released from area hospitals for injuries due to flying debris. The airport was closed due to the extensive damage.

The tornado exited Lambert St. Louis International Airport crossing near the McDonnell Boulevard/Harmon Lane intersection. It then moved into Berkeley where it crossed Interstate 170 between Airport Road and Scudder Avenue. Extensive damage was noted along Fourth Avenue, especially at the Garfield Avenue and Hancock Avenue intersections where a vacant house and several homes lost their entire roof structure. The greatest damage in this neighborhood was rated EF2. The tornado continued to the northeast through neighborhoods south of Airport Road producing significant tree damage including many large trees falling on homes. The tornado then crossed Airport Road near Abston Avenue. The tornado crossed North Florissant Road where it caused extensive roof damage to the Newer Materials building and the First Baptist Church of Ferguson. Across the road, a Little Caesars Restaurant lost it entire roof. Damage to these structures was rated EF1. The tornado then continued through neighborhoods along and just the north of Hereford Avenue/Chambers Road where it continued to cause extensive tree damage as well as some additional partial roof damage to homes along it path to West Florissant Road. Also along this part of its path, it partially removed the roof at the Griffith Elementary School which was rated as EF1. This is also where the tornado widened to one quarter of a mile with damage noted to trees and some homes on both sides of Chambers Road. Along the entire path from Berkeley to Dellwood, damage varied in intensity from EF1 to low end EF2 with a maximum estimated wind speed of 120 mph, and included numerous snapped power poles in addition to the extensive number of snapped and downed trees.

The tornadic damage continued southeast of the intersection of Chambers and Florissant Roads and traveled eastward south of Chambers road, crossing the Mississippi River approximately 2 miles south of Interstate 270. The majority of the damage was rated EF1 due to fallen trees. Some of these trees fell on homes while a few others fell through homes causing damage not directly relating to the intensity of the wind within the tornado.

EF2 damage was uncovered at three different locations east of Dellwood. One area was located one quarter mile south of Chambers Road on Halls Ferry Road where four large utility poles were snapped. The second area of EF2 damage was located 0.25 mile south of Chambers Road along Bellefontaine Road where significant tree damage occurred. The last area of damage was located in Bellefontaine Neighbors just south of Chambers Road on Ra Roux Court. Roofs were removed from three homes at this location, while other homes sustained varying degrees of damage.

The width of the damage area varies from 100 yards to 0.4 mile with the widest area of damage west of Halls Ferry and south of Chambers Road. The tornado entered illinois about 1.5 miles south of the Chain of Rocks Bridge. The tornado continued east to 0.5 mile north of the intersection of Highway 203 and Pontoon Road. Damage east of this intersection included uprooted and snapped trees and three homes had roofs removed. At least one hundred homes were damaged in the area. The maximum damage found was in a neighborhood along Bern and Dawn Streets. The tornadic damage then curved southeast and ended near the intersection of Alton Street and Pontoon Road. Damage width over this area varied from 50 to 150 yards. The damage east of Highway 203 was rated low-end EF2. The highest wind speeds associated with the EF2 damage were approximately 120 mph.

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