EF1 tornado, Granite City to Troy, Illinois, February 27, 2011

1. EF065 to 85 mph

   Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.

2. EF186 to 110 mphthis tornado

   Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.

3. EF2111 to 135 mph

   Considerable damage. Roofs torn off well-built houses, frame homes shifted on their foundations, mobile homes destroyed, large trees snapped or uprooted, cars lifted off the ground.

4. EF3136 to 165 mph

   Severe damage. Whole stories of well-built houses destroyed, large buildings badly damaged, trains overturned, trees debarked, heavy cars lifted and thrown.

5. EF4166 to 200 mph

   Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.

6. EF5over 200 mph

   Incredible damage. Strong frame houses swept off their foundations, car-sized missiles thrown more than 100 meters, steel-reinforced concrete badly damaged, high-rise buildings deformed.

7. Unrated

   The survey recorded a tornado but could not put a number on it, most often because it crossed open country and damaged nothing a rating can be read from.

Rating

EF1

Date

February 27, 2011

Touchdown

11:35 PM CST (05:35 UTC)

Lifted

11:38 PM CST (05:38 UTC)

On the ground

3 minutes

Path length

3.3 miles (5.2 km)

Path width

100 yards (91 m)

Deaths

0

Injuries

0

County

Madison County

Touchdown point

38.714, -90.164

Lift-off point

38.712, -90.104

Record number

1102272335-01

10 damage points were recorded along this path by NWS LSX, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF2. The highest wind the damage implies is 120 mph.

• Entire roof removed and thrown about 50 yards. Woman occupant injured. Serious head laceration.
• Park building damaged. New metal scoreboard destroyed.
• 2 very large fir trees uprooted at former home of Senator Paul Simon.
• Front porch covering torn from bar.

Survey points are preliminary and are the raw material the published rating was built from. Source: NWS Damage Assessment Toolkit.

A quasi-stationary frontal boundary was the main focusing mechanism for a round of significant severe weather over the forecast area. A strong shortwave moved along the boundary triggering widespread showers and thunderstorms. Numerous reports of large hail, damaging winds and 22 tornadoes occurred with this system.

It was determined that an EF1 tornado cut a 100 yard wide, over 3 mile long path through Granite City. The tornado first touched down at approximately 11:35 PM near the intersection of Illinois Route 3 and Rock Road. There, a large storage facility lost much of its roof. The tornado rapidly moved eastward at nearly 60 mph, causing significant tree and roof damage in its path. The tornado reached Maryville Road at around 11:38 PM where it dissipated.

The tornado touched down between Edwardsville and Glen Carbon near the intersection of Ginger Creek Drive and Illinois Route 157. There were several cedar trees uprooted at this location. The tornado continued east-northeast through the Ginger Creek Subdivision to the intersection of Center Grove Road and Illinois Route 159. This is where a metal industrial building sustained roof and siding damage. The tornado also crossed the intersection of Center Grove Road and Troy Road where a few signs of local businesses were damaged and a Home Depot sustained some damage to small preconstructed sheds sitting outside. The tornado continued east-northeast to near the intersection of Gerber Road and Governors Parkway where several houses sustained minor roof and siding damage. The tornado dissipated just beyond this location. The path length of this tornado was 2.4 miles long. Most of the damage along the path was rated EF0 with the maximum intensity rated EF1 for some tree damage and the industrial building damage. The maximum path width was 150 yards.

The tornado formed just west of Interstate 55 near Mick Road approximately 2 miles north of the Interstate 55/70/255 interchange where a few power poles were knocked over. The tornado crossed Interstate 55 and produced minor tree damage. It continued east-northeast where it produced roof and siding damage to a couple of homes. One home had part of the roof decking on the south side of the house removed while another had a flag pole located well to the north of the structure bent over almost to ground level. This pole was pointing south. Further along the path, a barn was destroyed along Staunton Road with debris strewn several hundred yards across the road into an open field. The tornado continued east-northeast until it snapped several mature pine trees off several feet above the ground along Nealy Lane. The tornado dissipated before reaching Illinois Route 4. The path length was 2 miles. The tornado had a maximum width of 50 yards and maximum intensity of EF1 for the destroyed barn and the snapped pine trees.

It was determined that a tornado touched down on Weathervane Road on the west side of Troy at approximately 11:45 PM. It was there that the tornado was at its strongest, an EF2, as it completely removed the roof from a well constructed home. One occupant received a serious head laceration and was treated at a local hospital. The tornado moved eastward at 60 mph, with a damage swath of 100 to 200 yards wide. Numerous trees, power lines, and roofs sustained minor to moderate damage along its path. The tornado continued to near the intersection of North Dewey Street and East Market Street, where it lifted at approximately 11:48 PM. The path length was 2.7 miles long.

From NOAA NCEI's Storm Events Database, the narrative the local forecast office wrote for Storm Data.

17 minutes of warning. NWS LSX issued a tornado warning for this county at 05:18 UTC, 17 minutes before the tornado touched down, in force until 06:00 UTC.

The county was under a tornado watch, issued at 03:40 UTC and running to 07:46 UTC.

Every warning and watch covering the touchdown point that day, from the Iowa Environmental Mesonet's archive of National Weather Service products. Lead time is measured from the issue of the warning in force to the touchdown time in the database, both of which were recorded to the minute by different people.

The Storm Prediction Center had this point in a Slight Risk, with a 0.10 chance of a tornado within 25 miles. The outlook in force was issued at 00:59 UTC.

SPC's Day 1 convective outlook as it stood when the tornado began, read at the touchdown point. The same archive is on the radar archive.

The radiosonde launches on either side of the tornado, from the nearest station that was launching then, drawn and analyzed the way Storm Lab does: the same diagram, the same parcel and shear definitions SPC's mesoanalysis uses.

Cahokia/St Louis (CPS), 16 km from the path, in the two hours either side.

From the Iowa Environmental Mesonet's archive of airport observations.

The St Louis radar (KLSX), 48 km away, was scanning. The volume nearest the touchdown began at 05:36 UTC.

Open the radar archive at this moment, over the track

Reflectivity and velocity, decoded from the Level II archive in the browser. Volumes take a few seconds to open the first time.

Local storm reports within 60 km of the path, in the three hours either side.

From the Iowa Environmental Mesonet's archive of National Weather Service local storm reports.

The live radar over the trackEvery 2011 tornado in IllinoisEvery tornado in Illinois since 1950Warnings in force in Illinois nowThe forecast where you are

19 more were confirmed in the United States that day.

Ratings are the survey's, read off the damage rather than measured; the rating scale is above. Tornado counts rise through the record as reporting improved, so a year in the 1950s is not comparable with one today except for the strongest tornadoes, which were always noticed.

NOAA Storm Prediction Center tornado database, 1950-2025, the official record kept by NOAA's Storm Prediction Center.