EF0 tornado, Woodruff, Kansas, June 1, 2011

1. EF065 to 85 mphthis tornado

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

2. EF186 to 110 mph

   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

EF0

Date

June 1, 2011

Touchdown

9:40 PM CDT (02:40 UTC)

Lifted

9:44 PM CDT (02:44 UTC)

On the ground

4 minutes

Path length

0.5 miles (0.7 km)

Path width

20 yards (18 m)

Deaths

0

Injuries

0

County

Phillips County

Touchdown point

39.992, -99.406

Lift-off point

39.993, -99.398

Record number

1106012040-01

Less than 48 hours after a line of damaging winds marched across North Central Kansas, a significant episode of severe weather targeted the six-county area on this Wednesday afternoon and early Thursday morning in the vicinity of a surface warm front. There were numerous reports of hail to golf ball size or larger across the area, and a few instances of damaging winds up to around 75 MPH. A brief EF0 tornado also occurred in far northern Phillips County. In addition, these storms drenched much of the area with torrential rainfall, bringing yet another round of significant flooding. Duration-wise, this was one of the most prolific severe weather events of the 2011 season, with at least one convective warning, and sometimes several, in effect at any given time for nearly 10 straight hours from around 4 PM to 2 AM CDT. A few of the more notable severe weather reports included 2-inch diameter hail in the Stockton and Natoma areas, and several power poles downed southeast of Alton. ||In terms of flooding, this was the third, and likely worst heavy rain event to strike this portion of North Central Kansas in a two-week span dating back to May 19th. Much of Smith, Jewell, Osborne and Mitchell Counties tallied 3-5 inches of rain. An observer at Ionia reported 4.59 inches from this event, bringing the total rainfall during the past nine days up to 9.57 inches. At one point in the evening, one foot of water was reported over Highway 14 in southern Mitchell County. Widespread rural flooding of creeks, streams and roads ensued as well, impacting various waterways including the Limestone, Oak and White Rock Creeks. Some evacuations were necessary northeast of Downs. Several main-stem rivers also went into flood, including the Solomon at Glen Elder and Beloit, North Fork Solomon at Portis, and South Fork Solomon at Woodston and Osborne. The gauges at Portis, Glen Elder and Beloit exceeded moderate flood stage, with Glen Elder cresting 5.76 feet over flood stage on the evening of the 2nd. ||This event essentially consisted of multiple, splitting supercell storms developing and tracking through the same areas. The first supercells initiated just west of the area around 330 PM CDT, quickly became severe, and rolled into Rooks and Phillips Counties by 430 PM. Although the initial volley of severe storms started to exit southern portions of Osborne and Mitchell Counties around 9 PM, considerable redevelopment soon took place farther west along the nose of a strong low-level jet. As a result, a whole new round of severe storms traversed the area for several more hours before finally exiting east of Jewell and Mitchell Counties by 2 AM, but not before producing gusts to 68 MPH at the Beloit airport. ||Although the mesoscale environment was supportive of severe weather, the long-lasting nature of this event was somewhat unexpected given a lack of large-scale forcing. The mid-levels featured only subtle, weak shortwave energy, well downstream from a powerful trough centered along the Pacific Northwest coast. However, deep-layer vertical wind shear around 40 knots, in combination with high mixed-layer CAPE values of 2500-4000 J/kg at the onset of the event made for a very conducive supercell environment. The primary instigator for multiple rounds of supercells was a persistent southerly low-level jet impinging over a surface warm front stretched from southwest Nebraska to east central Kansas. Winds along the nose of this jet at the 850-millibar level accelerated to 50 knots during the evening. This created very strong low-level wind shear and a mesoscale environment quite favorable for tornadoes. A review of radar data suggests that multiple storm-scale interactions, along with the outflow-dominant nature of some supercells likely spared North Central Kansas from a more significant tornado threat.

A brief tornado traveled about 1/2 mile across some farmland in rural northern Phillips County.

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

15 minutes of warning. NWS GID issued a tornado warning for this county at 02:25 UTC, 15 minutes before the tornado touched down, in force until 02:44 UTC.

The county was under a tornado watch, issued at 21:45 UTC and running to 04:49 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 0.05 chance of a tornado within 25 miles. The outlook in force was issued at 00:58 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.

The Grand Island radar (KUEX), 89 km away, was scanning. The volume nearest the touchdown began at 02:41 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 KansasEvery tornado in Kansas since 1950Warnings in force in Kansas nowThe forecast where you are

11 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.