With 11 confirmed tornadoes, several of them significant, this Monday afternoon proved to be the most active tornado day in over three years within South Central Nebraska, since 29 May 2008. This severe weather outbreak primarily targeted western and northeast portions of the area, largely sparing locations south of the Highway 6 corridor between Holdrege and Geneva. The final tornado breakdown per the EF Scale included two EF3, four EF2, two EF1 and three EF0. Despite considerable damage to mainly rural residences, these tornadoes resulted in no fatalities and only one known non-life threatening injury when a semi truck was tipped over near Elm Creek in Buffalo County. This Elm Creek tornado was also the only one to directly strike a community, although there were several close calls within a mile or two of places such as Amherst, Hampton and Bradshaw. Interestingly, tornadic storms also spared the immediate Tri-Cities population centers of Grand Island, Hastings and Kearney, despite damaging events occurring nearby to both the west and the east. This was largely due to the fact that an expansive mid-level dry intrusion became anchored over central sections of South Central Nebraska, protecting this area from storm development. In addition to tornadoes, the afternoon also featured several reports of large hail up to baseball size, and damaging winds up to 80 MPH.
This outbreak focused between 3 and 8 PM CDT, as a seasonably powerful mid-level low pressure system lifted into western Kansas and Nebraska out of Colorado, deepening and closing off as it did so. Strong wind fields aloft were in place at all levels, with a 50-70 knot jet streak nosing into the region between the 500 and 300 millibar level, and an 850-millibar low-level jet accelerating to between 30 and 40 knots. At the surface, a well-defined 992-millibar low pressure center migrated from north central Kansas around the noon hour, to near Hastings by early evening. A synoptically classic array of surface boundaries evolved around this low pressure center, with a warm front lifting north across South Central Nebraska, while a cold front and dryline pushed in from the west and southwest. In addition, a well-defined inverted surface trough axis extended nearly due north from the surface low into north central Nebraska. The net combination synoptic and mesoscale features yielded a very favorable setup for tornadic supercells across the area. At mid-afternoon, shear and instability parameters included approximately 50 knots of deep-layer vertical wind shear, 15-25 knots of 0-1 kilometer low-level vertical wind shear, 150 to over 300 m2/s2 of surface to 1 kilometer storm-relative helicity and 2000-4000 J/kg mixed-layer CAPE.
In general, there were two distinct corridors of tornadic storms across the area, one focused west of Highway 281, and one mainly east of Highway 281 and along and north of Interstate 80. The first tornadic storm of the day entered southwestern Harlan County around 3 PM CDT, having produced several damaging tornadoes across northwest and north central Kansas since early afternoon. This storm spawned an EF1 tornado in the Stamford area, before weakening. Within minutes however, a newly developed tornadic storm started tracking north from Phelps County into southwestern Buffalo County. Between 330 and 445 PM CDT, this storm dropped several tornadoes from near Elm Creek, to north of Amherst, including the first EF3 of the day. This EF3 near Amherst intensified to at least 3/4 of a mile wide, and significantly damaged or destroyed at least 10 homes. A veteran storm chaser described this tornado as being one of the strongest he had ever witnessed as it tracked north of Amherst. An additional tornadic storm that initiated in Buffalo County, along with subsequent storm-scale interactions from further development, moved north and produced several more tornadoes between 430 and 545 PM CDT, including an EF2 southwest of Rockville, and an EF1 that struck the Davis Creek Reservoir campground south of North Loup.
While tornadoes were ongoing across western portions of the area, vigorous new supercell development took place in eastern portions of South Central Nebraska around 430 PM CDT, just east of the surface triple-point. Two storms in close proximity to one another both became tornadic around 530 PM CDT near the Hamilton and York County line. The first produced an EF2 that crossed Interstate 80 southwest of Hampton. As this tornado moved north of Hampton, two farm workers fashioned a narrow escape by sprinting nearly 100 yards to an underground windmill pit and jumping inside as the tornado passed overhead. Just to the east, the other storm also dropped an EF2 tornado, which also happened to be the longest continuous tornado track of the day, traveling 15 miles from southwest of Bradshaw to near the York-Polk County line. Within a few minutes of this tornado's demise, the cyclic supercell quickly put down the second EF3 tornado of the day, tracking over 9 miles from east of Polk to west-northwest of Osceola. This tornado grew to around 1/2-mile wide, and damaged several farms along the way, with some of the most significant damage along Highway 92. After this tornado dissipated around 620 PM CDT, the parent supercell and other severe storms farther west finally lifted north out of South Central Nebraska. Although this ended the main severe weather event for the evening, a few additional strong to severe storms affected primarily Fillmore and Furnas Counties between 630 and 830 PM CDT.
Taking a backseat to significant tornadoes on this day were hail and heavy rainfall. Some of the largest reported hailstones included baseball size in Buffalo County, and tennis ball size in York County. Rainfall-wise, although there were no widespread flooding impacts, localized rural flooding occurred as many locations received 1-3 inches in a rather short time. Some northwestern portions of South Central Nebraska, including parts of Valley, Greeley and Sherman Counties measured 48-hour rainfall totals into the 3-4 inch range.

Hail in HALL, NEBRASKA
From 20-JUN-11 15:48:00 to 20-JUN-11 15:48:00 (CST-6)
Location: GRAND IS
Magnitude: 1.75 
Property damage: 25.00K
Crop damage: 250.00K
Reported by: Trained Spotter

Tornado in HOWARD, NEBRASKA
From 20-JUN-11 16:05:00 to 20-JUN-11 16:06:00 (CST-6)
Location: FARWELL
Tornado F-scale: EF0
Property damage: 80.00K
Crop damage: 0.00K
Reported by: Public

A tornado briefly touched down in a rural area approximately 5 miles west-southwest of Farwell.  One irrigation pivot was damaged by this tornado.

Thunderstorm Wind in HALL, NEBRASKA
From 20-JUN-11 16:12:00 to 20-JUN-11 16:12:00 (CST-6)
Location: GRAND IS
Magnitude: 52.00 EG
Property damage: 50.00K
Crop damage: 0.00K
Reported by: Law Enforcement

A large tree fell on a home near the intersection of Engleman and Abbott Roads on the west side of Grand Island.

Tornado in HAMILTON, NEBRASKA
From 20-JUN-11 16:25:00 to 20-JUN-11 16:45:00 (CST-6)
Location: HAMPTON
Tornado F-scale: EF2
Property damage: 2.50M
Crop damage: 500.00K
Reported by: NWS Storm Survey

This tornado touched down approximately 5 miles south-southwest of Hampton, just south of Interstate 80, where a home suffered some roof damage and a grain truck was overturned.  A cattle shed was also destroyed, trees were damaged, and a few wooden power poles were snapped.  A few moments later the tornado crossed over the interstate in front of many spectators.  Just north of the interstate, roof panels were ripped from an outbuilding and more power poles were broken.  A roof was partially removed from a double wide trailer just southwest of Hampton and irrigation pivots were knocked over.  The tornado continued on a path just west of Hampton, moving north-northeast.  Along its path, grain bins and irrigation pivots were destroyed, numerous tree trunks were snapped and irrigation piping was destroyed, including being wrapped around trees and power poles.  Approximately 60 power poles were destroyed, at least 16 irrigation pivots were damaged, along with 7 homes and 10 outbuildings. The tornado lifted 4 miles north northeast of Hampton, about 10 miles from its touchdown point.  The maximum wind speed of this tornado was estimated to be 125 MPH.

Hail in DAWSON, NEBRASKA
From 20-JUN-11 14:50:00 to 20-JUN-11 14:50:00 (CST-6)
Location: OVERTON
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Thunderstorm Wind in GREELEY, NEBRASKA
From 20-JUN-11 16:30:00 to 20-JUN-11 16:30:00 (CST-6)
Location: SPALDING
Magnitude: 70.00 EG
Property damage: 160.00K
Crop damage: 0.00K
Reported by: Newspaper

Wind gusts estimated at 80 MPH knocked over at least 2 irrigation pivots, destroyed a small grain bin and damaged a few power poles and trees.

Hail in YORK, NEBRASKA
From 20-JUN-11 16:34:00 to 20-JUN-11 16:34:00 (CST-6)
Location: BRADSHAW
Magnitude: 1.25 
Property damage: 5.00K
Crop damage: 150.00K
Reported by: Trained Spotter

Tornado in VALLEY, NEBRASKA
From 20-JUN-11 16:35:00 to 20-JUN-11 16:40:00 (CST-6)
Location: NORTH LOUP
Tornado F-scale: EF1
Property damage: 50.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

This tornado touched down near the Davis Creek Reservoir, or approximately 5 miles south of North Loup, and lifted approximately 4 miles south of North Loup.  At the Davis Creek Campground, it was estimated that 60 percent of the trees were damaged, and 2 restroom facilities suffered roof damage.  The maximum wind speed of this tornado was estimated to be 90 MPH.

Hail in YORK, NEBRASKA
From 20-JUN-11 16:35:00 to 20-JUN-11 16:35:00 (CST-6)
Location: BRADSHAW
Magnitude: 2.50 
Property damage: 50.00K
Crop damage: 1.00M
Reported by: Storm Chaser

Golf ball to tennis ball size hail was reported on Highway 34.

Thunderstorm Wind in DAWSON, NEBRASKA
From 20-JUN-11 14:50:00 to 20-JUN-11 14:50:00 (CST-6)
Location: OVERTON
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Wind gusts were estimated at 60 MPH.

Hail in BUFFALO, NEBRASKA
From 20-JUN-11 15:16:00 to 20-JUN-11 15:16:00 (CST-6)
Location: ELM CREEK
Magnitude: 2.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Fire Department/Rescue

Hail in BUFFALO, NEBRASKA
From 20-JUN-11 15:25:00 to 20-JUN-11 15:25:00 (CST-6)
Location: MILLER
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Hail in BUFFALO, NEBRASKA
From 20-JUN-11 15:35:00 to 20-JUN-11 15:35:00 (CST-6)
Location: MILLER
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Hail in HAMILTON, NEBRASKA
From 20-JUN-11 15:42:00 to 20-JUN-11 15:42:00 (CST-6)
Location: GILTNER
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Fire Department/Rescue

Hail in HALL, NEBRASKA
From 20-JUN-11 15:51:00 to 20-JUN-11 15:51:00 (CST-6)
Location: GRAND IS
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Hail up to the size of quarters was reported on the northwest side of Grand Island.

Tornado in YORK, NEBRASKA
From 20-JUN-11 16:40:00 to 20-JUN-11 17:00:00 (CST-6)
Location: HENDERSON
Tornado F-scale: EF2
Property damage: 3.50M
Crop damage: 500.00K
Reported by: NWS Storm Survey

This tornado touched down approximately 4 miles southwest of Bradshaw, moving to the north-northeast and dissipating approximately 4 miles southeast of Polk, near the York and Polk County line.  As the tornado approached Highway 34 west of Bradshaw, a metal outbuilding and grain bins were destroyed, and it also crossed a railroad line, derailing several train cars.  North of Bradshaw, a home suffered significant roof damage and the loss of one wall, and as the tornado continued north, power poles were snapped, irrigation pivots were overturned, and several trees were damaged.  Between Bradshaw to the area west of Benedict, a total of 40 power poles were downed. The maximum wind speed of this tornado was estimated to be 130 MPH.

Hail in HALL, NEBRASKA
From 20-JUN-11 15:59:00 to 20-JUN-11 15:59:00 (CST-6)
Location: GRAND IS
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Nickel size hail was reported near the intersection of Highway 281 and Husker Highway.

Hail in HALL, NEBRASKA
From 20-JUN-11 16:00:00 to 20-JUN-11 16:00:00 (CST-6)
Location: GRAND IS
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Quarter size hail was reported on the southwest side of Grand Island.

Hail in HAMILTON, NEBRASKA
From 20-JUN-11 16:01:00 to 20-JUN-11 16:01:00 (CST-6)
Location: AURORA
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Nickel size hail was reported south of Aurora on Highway 14.

Hail in FILLMORE, NEBRASKA
From 20-JUN-11 18:27:00 to 20-JUN-11 18:27:00 (CST-6)
Location: EXETER
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Thunderstorm Wind in DAWSON, NEBRASKA
From 20-JUN-11 14:44:00 to 20-JUN-11 14:44:00 (CST-6)
Location: OVERTON
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Wind gusts were estimated at 60 MPH on Interstate 80.

Hail in HAMILTON, NEBRASKA
From 20-JUN-11 16:26:00 to 20-JUN-11 16:26:00 (CST-6)
Location: AURORA
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Hail in YORK, NEBRASKA
From 20-JUN-11 16:29:00 to 20-JUN-11 16:29:00 (CST-6)
Location: HENDERSON
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Tornado in POLK, NEBRASKA
From 20-JUN-11 17:02:00 to 20-JUN-11 17:20:00 (CST-6)
Location: DURANT
Tornado F-scale: EF3
Property damage: 4.00M
Crop damage: 500.00K
Reported by: NWS Storm Survey

The second EF3 tornado of the day touched down approximately 4 miles east of Polk and continued north for nearly 10 miles before lifting approximately 6 miles west-northwest of Osceola.  Damage was noted right at the start of the path, with a brick home on Highway 66 west of Polk suffering significant roof, window and tree damage, and a semi-truck and trailer were knocked over onto its side.  About 2 miles north of Highway 66, a residence suffered minor tree damage and lost an outbuilding, and a combine was tossed about 100 yards into a field.  As the tornado continued north, numerous power poles were snapped, irrigation pivots were overturned, and crops were stripped from the ground. The most significant damage occurred when a farmstead on Highway 92 approximately 6 miles west of Osceola took a direct hit.  The home as well as surrounding outbuildings and trees were either destroyed or suffered significant damage.  A car, tractor, and an ATV were thrown from their original locations into the field just north of the home.  The tornado finally lifted approximately 2 miles north of the intersection of Highways 92 and 39, but not before striking another farmstead, destroying an outbuilding and garage, and damaging a machine shed and barn.  The maximum wind speed of this tornado was estimated to be 140 MPH.

Tornado in HARLAN, NEBRASKA
From 20-JUN-11 14:00:00 to 20-JUN-11 14:32:00 (CST-6)
Location: STAMFORD
Tornado F-scale: EF1
Property damage: 250.00K
Crop damage: 250.00K
Reported by: Law Enforcement

This tornado skipped along a path which started approximately 8 miles south of Stamford and ended approximately 4 miles north of Stamford.  It was noted that this tornado was stationary and multi-vortex early on in its life, and as it shifted to the north destroyed an outbuilding, quonset, and grain bin.  Numerous tree limbs were also knocked down.  The maximum wind speed of this tornado was estimated to be 95 MPH.

Hail in HARLAN, NEBRASKA
From 20-JUN-11 14:05:00 to 20-JUN-11 14:05:00 (CST-6)
Location: STAMFORD
Magnitude: 1.75 
Property damage: 100.00K
Crop damage: 5.00M
Reported by: Law Enforcement

Hail up to the size of golf balls was reported, causing damage to area windows and crops.

Tornado in PHELPS, NEBRASKA
From 20-JUN-11 14:35:00 to 20-JUN-11 14:45:00 (CST-6)
Location: WESTMARK
Tornado F-scale: EF0
Property damage: 500.00K
Crop damage: 250.00K
Reported by: NWS Storm Survey

This tornado touched down in northern Phelps County, approximately 6 miles south-southwest of Elm Creek, and moved north into southern Buffalo County, dissipating just south of Elm Creek.  This tornado lifted and touched back down several times along its path, with the main damage coming from overturned irrigation pivots.  The maximum wind speed of this tornado was estimated to be 80 MPH.

Hail in DAWSON, NEBRASKA
From 20-JUN-11 14:44:00 to 20-JUN-11 14:44:00 (CST-6)
Location: OVERTON
Magnitude: 1.50 
Property damage: 250.00K
Crop damage: 250.00K
Reported by: Law Enforcement

Hail up to the size of ping pong balls was reported on Interstate 80.

Tornado in BUFFALO, NEBRASKA
From 20-JUN-11 14:45:00 to 20-JUN-11 14:52:00 (CST-6)
Location: ELM CREEK
Tornado F-scale: EF0
Property damage: 250.00K
Crop damage: 250.00K
Reported by: NWS Storm Survey

This tornado touched down in northern Phelps County, approximately 6 miles south-southwest of Elm Creek, and moved north into southern Buffalo County, dissipating just south of Elm Creek.  This tornado lifted and touched back down several times along its path, with the main damage coming from overturned irrigation pivots.  The maximum wind speed of this tornado was estimated to be 80 MPH.

Hail in DAWSON, NEBRASKA
From 20-JUN-11 14:45:00 to 20-JUN-11 14:45:00 (CST-6)
Location: OVERTON
Magnitude: 1.75 
Property damage: 25.00K
Crop damage: 250.00K
Reported by: Trained Spotter

Tornado in BUFFALO, NEBRASKA
From 20-JUN-11 14:51:00 to 20-JUN-11 15:07:00 (CST-6)
Location: ELM CREEK
Tornado F-scale: EF2
Property damage: 750.00K
Crop damage: 500.00K
Reported by: NWS Storm Survey

While the tornado south of Elm Creek was in the process of dissipating, a second tornado formed approximately 1 mile west of Elm Creek.  This multi-vortex tornado moved east into town, and caused widespread damage, before making a sharp turn to the north and dissipating approximately 4 miles north of Elm Creek.  Much of the damage occurred to trees, however several homes received damage, including major roof damage to homes in both the north and south parts of Elm Creek.  Outbuildings were also destroyed in the northwest part of town.  One non-life threatening injury occurred to a man whose semi-truck was tipped on its side by the tornado. The maximum wind speed of this tornado was estimated to be 120 MPH.

Hail in BUFFALO, NEBRASKA
From 20-JUN-11 15:16:00 to 20-JUN-11 15:16:00 (CST-6)
Location: GIBBON
Magnitude: 1.00 
Property damage: 50.00K
Crop damage: 500.00K
Reported by: Trained Spotter

Hail in BUFFALO, NEBRASKA
From 20-JUN-11 15:19:00 to 20-JUN-11 15:19:00 (CST-6)
Location: GIBBON
Magnitude: 2.00 
Property damage: 25.00K
Crop damage: 350.00K
Reported by: Storm Chaser

Tornado in BUFFALO, NEBRASKA
From 20-JUN-11 15:35:00 to 20-JUN-11 15:50:00 (CST-6)
Location: PLEASANTON
Tornado F-scale: EF0
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

This tornado skipped along a path which started approximately 3 miles southeast of Pleasanton and ended approximately 2 miles northeast of Pleasanton.  No damage was reported with this tornado.

Tornado in BUFFALO, NEBRASKA
From 20-JUN-11 15:09:00 to 20-JUN-11 15:37:00 (CST-6)
Location: ELM CREEK
Tornado F-scale: EF3
Property damage: 6.00M
Crop damage: 2.00M
Reported by: NWS Storm Survey

After producing tornadoes in the Elm Creek area, this supercell thunderstorm continued on a northward path and produced what would be the strongest and one of two EF3 tornadoes of the day.  This tornado touched down approximately 5 miles southwest of Amherst, curving to the north-northeast and missing the town by around 2 miles, before dissipating approximately 4 miles north of Amherst.  Soon after the tornado touched down, a home suffered significant damage, and as the tornado crossed Highway 40, it intensified and produced a damage path at least 3/4 of a mile wide.  The tornado knocked down large transmission lines along Highway 40, and overturned irrigation pivots.  As it continued to the northeast, the tornado destroyed one home directly in its path, and no walls remained standing.  Taking a turn more to the north, damage continued as outbuildings were destroyed and large metal truss towers were knocked down.  Tree trunks were snapped and an irrigation pivot was knocked over approximately 4 miles north of Amherst.  The emergency manager later noted that a total of 4 homes were destroyed, 6 to 8 had substantial damage, and 30 others suffered minor damage.  Forty irrigation pivots were also either damaged or destroyed.  The maximum wind speed of this tornado was estimated to be 160 MPH.

Tornado in SHERMAN, NEBRASKA
From 20-JUN-11 15:46:00 to 20-JUN-11 15:54:00 (CST-6)
Location: ROCKVILLE
Tornado F-scale: EF2
Property damage: 100.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

This tornado touched down approximately 6 miles southwest of Rockville, moving to the north before taking a turn to the east as it approached the intersection of Highways 68 and 82A, and lifted approximately 4 miles southwest of Rockville.  Along the path of this tornado, a pole building was destroyed and a home and surrounding trees sustained minor damage.  The maximum wind speed of this tornado was estimated to be 120 MPH.