Tornado and Hail Event over
During the afternoon and early evening hours of Monday, October 18th, 2004 a severe weather outbreak occurred across the eastern Ozarks, southeast Missouri, and southern Illinois. A warm front draped across Missouri and Illinois sperated two very different airmasses. To the north of the front, temperatures were only in the upper 40s with a persistent east wind, while to the south of the front, southerly winds and mostly sunny skies allowed a very warm, moist, and unstable atmosphere to pool across the southern half of Missouri. As the powerful upper level system and surface dryline crossed the Mid-Mississippi River Valley, convection erupted across the eastern Ozarks. A favorable vertical shear profile in the atmosphere allowed the convection to quickly develop into rotating thunderstorms, also known as supercells. Tornadoes, severe hail, and damaging winds were reported with these storms as they tracked across southeast Missouri into southwest Illinois.
Damage surveys conducted by National Weather Service personnel revealed that nine tornadoes hit parts of Washington...Iron...and Madison counties. Two supercell thunderstorms were responsible for the tornadoes. One storm produced five tornados in Washington County while the other produced two tornadoes in Iron County and two in Madison County.
Washington County Tornadoes
A series of 5 weak tornadoes formed quickly and moved across parts of central Washington County Missouri.
The first tornado occurred about 408 pm cdt and damaged the Potosi lumberyard about 0.5 mile northeast of Potosi along highway 21. Three buildings were severely damaged by the tornado. Seven people were injured. One was kept overnight at a local hospital while the other six were treated and released. The overall damage path was about 0.2 mile long and 80 yards wide. The tornado was rated F1.
The second tornado started about 410 pm cdt about 1 mile northeast of Potosi and moved northeast along Highway E. One home, one mobile home and a storage building were damaged. Several trees were either uprooted or snapped off. This tornado was about 0.75 mile long, 50 yards wide and was rated F0.
About one minute later, the third tornado was observed in an open field about 1.5 miles east northeast of Potosi. A few large trees were uprooted or snapped off along a 0.75 mile track that was 40 yards wide. The tornado was rated F0.
The fourth and fifth tornadoes affected the town of Mineral Point. The fourth tornado was first observed about 412 pm cdt and traveled northeast for 0.75 mile across the central part of town. One home and several mobile homes sustained varying degrees of damage. Several large trees were snapped off and others pushed over. The damage path was about 0.75 mile long and 40 yards wide. The tornado was rated F0.
The fifth tornado was spotted at almost the same time and started on the southeast side of Mineral Point. One home suffered minor roof damage and several mobile homes were also damaged. Trees were snapped off or uprooted. The overall damage path was 0.75 mile long and 40 yards wide. The tornado was rated F0.
Hail at least 2 inches in diameter fell before the tornadoes in Mineral Point.
Iron and Madison County Tornadoes
A National Weather Service damage survey revealed that a supercell thunderstorm produced four tornadoes across Iron and Madison counties...from Ironton to northeast of Fredericktown.
The first tornado occurred from about 426 pm to 430 pm cdt and first caused damage on the north end of Shepherd Mountain Lake. Trees were downed and damaged on both sides of the lake as the tornado moved east at about 40 miles an hour. The tornado moved into western portions of Ironton downing and snapping off trees on West Boulder Drive. On Lake Drive, part of the roof of the Iron County Health Department was blown off and landed about 75 yards away. A storage shed in this same area was also destroyed with part of it landing in power lines. The majority of the damage was due to downed and snapped off trees. Power lines and poles were down primarily because of the trees and limbs. About a dozen homes suffered minor damage involving downed trees or roof shingles blown off. One car was damaged by a large tree limb. The maximum width of the damage was 400 yards and the damage path was 1.8 miles. The tornado was given a rating of F1 with top winds of 75 to 100 miles an hour. Hail up to golfball size fell before the tornado.
The second tornado was small and short lived and struck 3 miles east of Ironton in the Killarney Shores area. This tornado hit about 435 pm cdt and downed and snapped off trees along a 0.5 mile long and 100 yard wide path. This tornado was rated F0.
The third tornado occurred along a 1.5 mile long, 250 yard wide path about 3 miles northwest of Fredericktown in Madison county. Witnesses observed the tornado form in an open field and then moved east crossing Highway H and causing damage at the Country Star Community Mobile Home Park. The majority of the damage was from downed trees or large tree limbs. A home just south of the park suffered major damage from a large downed tree. Another home just east of the park suffered minor roof damage and had four windows blown in. The tornado crossed U.S. Highway 67 near County Road 220 and caused damage in the White Tail Crossing neighborhood. Trees were downed and snapped off in the neighborhood. This tornado was rated F0 and occurred from about 459 pm to 502 pm CDT.
The fourth tornado first caused damage about 510 pm CDT, 3 miles north northeast of Fredericktown. The tornado crossed County Road 217 and blew off parts of the roof of a barn, caused minor roof damage to a home and downed and snapped off trees. The tornado moved east and destroyed a stand alone garage at a home on County Road 219 just north of County Road 221. The owner of the home was outside and saw the tornado coming. He moved inside to an interior bathroom for shelter just before the tornado arrived. The tornado continued east causing intermittent tree damage. The next significant damage occurred near the end of the tornado's track just north of Higdon along County Road 257. A home had most of the roof shingles blown off and a couple of windows blown in. The owner commented that he ended up with about 2 inches of leaves in his home. A trampoline in the backyard was picked up, blown to the north and wrapped around a tree. A 14 foot boat that was on a pond behind the house ended up about 100 yards away suspended in some trees. This tornado had a total damage path of 5.5 miles and a maximum width of 100 yards. It was rated F1.