EF1 tornado, Giltner to Hordville, Nebraska, December 15, 2021

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

December 15, 2021

Touchdown

2:11 PM CST (20:11 UTC)

Lifted

2:19 PM CST (20:19 UTC)

On the ground

8 minutes

Path length

12.9 miles (20.8 km)

Path width

400 yards (366 m)

Deaths

0

Injuries

0

Property damage

$500,000

County

Hamilton County

Touchdown point

40.724, -98.112

Lift-off point

40.892, -98.002

Record number

2112151411-01

51 damage points were recorded along this path by NWS GID, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF1. The highest wind the damage implies is 100 mph.

• Center Pivot tipped and twisted. 8 Station pivot. Damage is about 100 yards east of where picture was taken.
• Center irrigation pivot flipped. Location approximately 200 yds to east of photo location.
• Large Spruce Tree Uprooted.
• End of tornado damage. Just a few more tree branches down.

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

A historic onslaught of swift moving severe thunderstorms with embedded tornadoes, followed by several hours of severe gradient winds and areas of blowing dust/smoke (and even a touch of wind-whipped snow) unfolded within South Central Nebraska on this Wednesday afternoon-evening, with the local area serving as the initiation zone of what would not only end up being the most impactful convective event on record during the month of December for the state of Nebraska (far eclipsing Christmas Day 2016), but also for other nearby states including IA/MN. In fact, the nearly continuous swath of damaging winds that stretched from south central NE/north central KS northeastward into southeast MN/western WI was officially declared a serial derecho...the first December derecho on record in the United States. Including nine confirmed tornadoes in South Central Nebraska (and 19 others that occurred in eastern NE), there were 28 confirmed tornadoes within the state...a remarkable fact considering that prior to this day only five Nebraska tornadoes had occurred in December since 1950! Focusing exclusively on the local South Central NE area going forward, the nine tornadoes consisted of five rated EF-1 and four rated EF-0. There were also dozens of measured reports of damaging winds in the 60-80+ MPH range (both thunderstorm/non-thunderstorm), including a peak thunderstorm gust of 85 MPH at Central Nebraska Regional Airport in Grand Island and a peak non-thunderstorm gust of 77 MPH by an unofficial mesonet in southwestern Clay County. Fortunately, there were no reported injuries, despite countless instances of damage primarily to irrigation pivots, outbuildings, power lines/poles and trees. ||Breaking down event evolution/timing for the local area, first of all, even before convection flared up it was already an unusual/noteworthy December weather day given unseasonable warmth/humidity being pumped into the area on strong south winds. By late morning-early afternoon, southerly gusts were commonly 35-50 MPH as temperatures soared into the mid-60s to low-70s F (setting new Dec. 15th records in Grand Island/Hastings), accompanied by dewpoints surging at least briefly into the 50s F (mainly near/east of Highway 281). This set the stage for severe convection/tornadoes during the early-mid afternoon, as the squall line that eventually impacted all but a few far western local counties raced through South Central NE at an incredible average forward motion of 65-75 MPH. The squall line, which was still in its infant stages as it entered Harlan County out of Kansas shortly before 1 p.m., rapidly intensified/expanded in scope while reaching the Highway 281 corridor by 2 p.m., and then in the blink of an eye had all-but-exited the extreme eastern fringes of the local area (Highway 81 counties) by 3 p.m....wrapping up a brief-but-wild two hours of weather. As for the nine confirmed South Central NE tornadoes, they all occurred between 1:27-2:43 p.m. and had at-times-intermittent path lengths between 7-15 miles. The tornadoes concentrated within counties mainly situated between the Highway 92 and Highway 6 corridors, touching down as far west as eastern Kearney/Franklin counties and as far east-northeast as Hamilton/Polk counties. The circulations were firmly embedded within the aforementioned squall line, making these quasi linear convective system (QLCS) tornadoes with often-intermittent damage paths. As is typical of such tornadoes, there was little in the way of clear cut photographic/video evidence, with the main exception consisting of a more classic looking photo of an EF-1 near Marquette. Although specific details regarding each of the nine tornadoes can be found in their respective event narratives, the vast majority of damage occurred to irrigation pivots, power poles/lines and a handful of outbuildings/grain bins, including a few fairly large metal outbuildings that were partially or completely demolished within only a few miles of communities such as Hastings, Marquette and Polk. Fortunately, no homes suffered major damage, although a few sustained relatively minor roof/siding issues. And although there were no reported injuries, one family north of Hastings had a fairly close call as their sport utility vehicle had several windows blown out of it only about one minute after they arrived home and sought shelter. Although straight-line thunderstorm winds along the surging line took a publicity backseat to the tornadoes, there were dozens of reported measured/estimated gusts of at least 60-70 MPH, and a handful of measured gusts as high as 75-85 MPH, highlighted by 85 MPH at Central Nebraska Regional Airport (official) and unofficial mesonet gusts of 84 MPH near Shickley, 83 MPH near Davenport and 81 MPH near Oxford. As just a sampling of damage attributed to convective winds: a blown-over semi truck on Highway 6 near Hastings; an overturned pickup truck and trailer along I-80 near Grand Island; significant roof and siding damage to a brick building in downtown Giltner; a metal outbuilding largely destroyed near Fullerton; a carport lofted into power lines in Bruning. Lastly in the convective department, hail was a minimal issue for the vast majority of South Central Nebraska. However, stones up to golf ball size significantly damaged a home near Marquette, while slightly smaller, wind-driven hail up to quarter size was reported in the Grand Island and Hastings areas, including a report of considerable damage to siding, fences and shingles in the Lake Hastings area.||Turning to non-convective severe winds, for the majority of South Central Nebraska they peaked in intensity a few hours after the passage of the squall line (and also impacted those few far western counties that were spared by convection), ramping up initially from the southwest and eventually west-northwest behind a surging composite cold front/dryline. Generally speaking, roughly the southwestern half of the local area observed its strongest non-convective winds between 2-7 p.m., while the northeastern half of the area peaked more so 4-9 p.m. However, the entire area endured at least a few hours of sustained speeds commonly 30-45 MPH and sporadic gusts of 50-70 MPH, including official peak gusts of 73 MPH at Hastings and Ord airports, and unofficial peak mesonet gusts of 77 MPH near Glenvil, 76 MPH near Davenport and 75 MPH near Norman. Although these non-convective winds undoubtedly caused considerable minor damage and/or exacerbated damage already done by earlier convective winds, specific reports were actually quite limited. However, one unique highlight of these southwesterly-turning-westerly winds is that they shrouded much of the local area a under an eerie pall for a few hours during the mid-late afternoon...a combination of blowing dust (emanating off the western High Plains) and also smoke (from large wildfires in northern KS) that reduced visibility to under a mile in some spots. Fortunately, no wildfires were sparked within South Central NE itself, despite favorable conditions for large fire growth behind the dryline (especially in southwestern counties). The final severe-criteria gust of the evening (59 MPH) occurred in Nance County shortly after 7 p.m., and gusts eased down to only 30-40 MPH within most of South Central NE by 10 p.m.||The last weather element of this multi-faceted event (and ironically of least-overall impact for December) was snow, as far western/northwest portions of the local area observed roughly a one-hour period of wind-whipped snow between 3:30-5:30 p.m. as a weakening deformation zone on the backside of the system clipped parts of mainly Dawson, Sherman, Valley and far western Buffalo counties. Although total accumulations were mainly at-or-below one-half inch and there were no reports of significant travel impacts, the fact that this snow band prompted brief, greatly-reduced visibility reductions along Interstate 80 prompted the first-ever Snow Squall Warning issuance within South Central NE.||Examining the meteorology behind this event, this would have been considered a powerhouse setup for severe convection/high winds during the more typical spring season usually associated with this type of system, let alone in mid-December. In the mid-upper levels, not only was the parent, negatively-tilted shortwave trough notably intense as it slammed across the central United States, but it was also notably fast. At daybreak, its vorticity maximum was just passing by the Four Corners, but by mid-day it had already reached the NE/CO/KS border area and by sunset had advanced into far northeast NE. At the 500-millibar level, a stout jet streak of 100+ knots nosed into South Central NE from the south-southwest during the afternoon, while lower in the column a potent southerly low level jet (evident at 850 millibars) ramped up to 40-60 knots. At the surface, a vigorous low pressure center sliced across the heart of Nebraska from southwest-to-northeast during the afternoon, deepening to around 984 millibars along the way and driving a sharp dryline/cold frontal combo eastward through the area. As mentioned, surface dewpoints climbed into the 50s F across much of the area prior to convective initiation, fostering a corridor of mixed-layer CAPE up to 500-1000 J/kg. Although somewhat modest instability values by warmer-season standards, in this case it was more than enough to promote robust severe convection in the presence of extreme wind fields, with embedded QLCS tornadoes no surprise given 0-1 kilometer bulk shear around 40 knots and effective storm-relative helicity (SRH) around 200-300 m2/s2. In the wake of the squall line, the ensuing non-convective wind event corresponded to a zone of deep subsidence (likely associated with a sting jet) and a pronounced surface pressure gradient on the backside of the departing low, with a 16-millibar gradient noted across South Central NE at 6 p.m. (ranging from 988 mb at Columbus to 1004 mb at McCook).||Closing with some comments about official NWS forecasts leading up to this historic event, there was excellent awareness several days in advance regarding the likelihood of powerful non-convective winds both ahead of (southerlies) and behind (westerlies) the intense surface low pressure system. An area-wide High Wind Watch was issued early on the 13th (48-60 hours in advance) and was subsequently upgraded to a High Wind Warning early on the 14th. However, what was not as well anticipated (both at the local and national forecast level) was how great of a convective/tornado threat South Central NE would face, as the fast-tracking squall line ended up forming slightly earlier and several counties farther west than most model data suggested (especially 12+ hours out). As a result, there was a noticeable ramp-up of convective threat categories within South Central NE on Dec. 15th SPC Day 1 Outlooks, progressing from the initial 06Z outlook that barely brushed the far eastern fringes of the area with a Marginal Risk (level 1 of 5), to the 1630Z outlook that correctly shifted Slight (level 2) and Enhanced (level 3) categories westward into several counties along/east of Highway 281.

This tornado touched down in extreme northeast Adams County south of Trumbull, crossed through far northwest Clay County before heading into southwest Hamilton County. This intermittent tornado damaged a horse barn south of Trumbull as it began its roughly seven-mile path. As it moved northeast, most of the observable damage was to a couple of irrigation pivots along with a snapped tree. The estimated maximum wind gust was 75 MPH.

This Hamilton County tornado touched down four miles southeast of Giltner and traveled northeast into Aurora. The estimated maximum wind gust of 100 MPH was based mainly upon snapped power poles. There were numerous irrigation pivots damaged along and near this path. The tornado crossed Interstate 80 approximately two miles west of the Aurora interchange. The tornado entered the southwest side of Aurora near the fairgrounds. Metal cladding was peeled from storage facilities nearby and there were several spots of tree damage. The tornado lifted around 12th and E Streets just south of the railroad tracks.

This tornado touched down in northeast Hamilton County near Kronborg and moved northeast into southwest Polk County. This tornado was one of the more classic-looking tornadoes of the day, based on photos reviewed. The estimated maximum wind speed of 100 MPH was based primarily upon snapped power poles, but a hog facility was also heavily damages about 2 miles into the path of this tornado. The tornado crossed Highway 66 about two miles west of Polk. Just before it lifted north of Polk, the tornado took down a large metal building.

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

14 minutes of warning. NWS GID issued a tornado warning for this county at 19:57 UTC, 14 minutes before the tornado touched down, in force until 20:15 UTC.

The county was under a tornado watch, issued at 19:29 UTC and running to 21:03 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 0.02 chance of a tornado within 25 miles. The outlook in force was issued at 19:28 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.

Aurora (AUH), 11 km from the path, in the two hours either side.

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

The Grand Island radar (KUEX), 63 km away, was scanning. The volume nearest the touchdown began at 20:12 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 2021 tornado in NebraskaEvery tornado in Nebraska since 1950Warnings in force in Nebraska nowThe forecast where you are

124 more were confirmed in the United States that day.

All 125 of them

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.