EF1 Tornado — Racine, Wisconsin

2010-11-22 · near Union Grove, Racine, Wisconsin

Event narrative

This tornado is a continuation of a segment that started in Kenosha County. It quickly intensified to an EF-1 rating after moving into Racine County. It moved into southern Racine County about 2.3 miles southwest of Union Grove, around 1,700 feet to the east of the intersection of County Line Road and 224th Avenue. The tornado moved northeast before dissipating near the intersection of County Highway K and County Highway H, about 1/2 mile southeast of Franksville. There were no fatalities, but 2 people were injured in storm-related vehicle accidents. Newspaper articles indicated they were hospitalized. Union Grove bore the brunt of the damage. Eleven buildings, fencing, and trees were damaged on the Racine County Fairgrounds. Large oak trees in Old Settler's Park, which is the northwest corner of the Racine County Fairgrounds, were hit hard. Across the street (STH 11), two businesses had large pieces of roof covering peeled off. One of these, Grove Gear, had about 10,000 square feet of it's roof ripped off, which allowed rain to damage the inside offices and equipment. Newspaper articles indicated that damage to Grove Gear alone was about $1.4 Million. Two other businesses also had roof and siding damage. A residential-care facility had several of its buildings damaged. Around 100 homes in the Village of Union Grove sustained light to moderate damage to roofs, windows, and/or siding, and numerous trees were either uprooted or had large branches broken or snapped. Numerous gas leaks in and around Union Grove were reported. Only one home was extensively damaged and had to be demolished. A semi-trailer truck overturned on Interstate 94 near State Highway 20, blocking the northbound lanes, as the tornado crossed the interstate. Another semi-trailer was blown over on eastbound Highway 20 near the west frontage road next to the interstate. A number of campers were overturned and one was destroyed at the Burlington RV store at the intersection of STH 20 and Interstate-94. WeEnergy Utility estimated that 3200 customers lost electrical power in Racine County. The path of the tornado averaged 75 yards in width. A detailed examination of the tornado path suggests that this tornado consisted of three or four individual vortices, with one taking over as the previous one dissipated. Each vortex had it own path, which resulted in segmented-appearance of the tornado path as shown in the associated image attached to this severe weather episode. Although the header strip for this tornado event indicates a path length of 10.57 miles, a manual map measurement value of 10.67 miles was obtained. The total loss estimate of $5M was received from Racine County Emergency Management. The EF1 estimated wind speed of 105 mph was based on DI 21(MBS) DOD 3. The exact start location is Lat 42.66995 Lon -88.07447. The exact end location is Lat 42.75586 Lon -87.90231.

Wider weather episode

An out-of-season round of strong to severe, surface-based, thunderstorms developed in Southeast Wisconsin during the mid-afternoon of November 22nd, which resulted in two tornadoes. This severe weather was related to low pressure lifting northeast from southwestern to central Wisconsin which brought a warm front up into southern Wisconsin. Afternoon temperatures peaked in the lower to mid 60s In the counties of Walworth, Racine, and Kenosha, with dewpoints reaching the mid to upper 50s. Instability with the unseasonable warmth just south of the warm front, with surface based CAPE values between 500 J/kg to 1000 J/kg, allowed for the thunderstorm development. Strong lift associated with the right entrance region of a 50 to 60 knot mid-level jet, strong deep layer shear and steep mid level lapse rates allowed super-cell thunderstorms with rotating updrafts to fire up along and ahead of a cold front trailing south of the low. Strong low-level shear developed just south of the warm front which led to one tornado in Walworth County and the other from far northern Kenosha County into southern Racine County around Union Grove. About 3,000 customers lost electric power due to the tornadoes and accompanying thunderstorms.

View location on OpenStreetMap → (42.6700, -88.0745)

Source: NOAA Storm Events Database, event_id 263879. Narrative written by the NWS forecast office that issued the report.