EF3 tornado, Aneta to Northwood, North Dakota, August 26, 2007

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 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 mphthis tornado

   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

EF3

Date

August 26, 2007

Touchdown

8:04 PM CDT (01:04 UTC)

Lifted

8:16 PM CDT (01:16 UTC)

On the ground

12 minutes

Path length

6.0 miles (9.7 km)

Path width

580 yards (530 m)

Deaths

0

Injuries

0

Counties

Nelson and Grand Forks counties

Touchdown point

47.760, -97.931

Lift-off point

47.840, -97.845

Record number

0708261904-01

A cold front moved across North Dakota on the 26th, with a hot and humid airmass in place ahead of the front. At 6 pm CST, a surface low was located over southern Manitoba (Canada), just north of Pembina, ND. The cold front stretched to the southwest, back toward Devils Lake (ND) and Bismarck (ND). Ahead of the cold front, temperatures ranged in the low to mid 80s with dew points around 70F. Behind the front, temperatures did not cool significantly, but dew points dropped to the mid 40s. Thunderstorms began to form along and ahead of the cold front by early evening (from northeast ND into south central ND), eventually crossing into northwest Minnesota several hours later. Eight distinct tornadoes occurred over northeast North Dakota and northwest Minnesota during this event.

This tornado continued into western Grand Forks County, where it dissipated 3 miles west-northwest of Logan Center at 716 pm CST. The total tornado track was about 6 miles long, with about 5 miles of this total occurring in Nelson County. The tornado destroyed a garage and farm outbuildings at 3 farmsteads. It killed 5 buffalo and completely dismantled a swathing combine. Trees were also snapped off or uprooted along the damage path and several empty metal grain bins were torn from their anchors and demolished. Gravel roads were deeply scarred by debris. Peak winds were estimated at 150 mph.

This tornado began about 6 miles north-northeast of Aneta in eastern Nelson County at 704 pm CST. The total tornado track was about 6 miles, with about 1 mile of it occurring in Grand Forks County. The tornado lofted and destroyed a second combine in Grand Forks County before it lifted. Peak winds were estimated at 150 mph.

The tornado touched down about 2 miles west-southwest of Northwood. The tornado crossed the Goose River about a mile west-southwest of the Northwood airport and left a 200 yard wide stretch of downed trees in its wake. By the time it hit the airport, the ground track was one-third of a mile wide and growing wider. At this point the tornado was still visible outside the increasingly heavy rain. ||The tornado reached an incredible width of eight-tenths of a mile as it pushed through Northwood to the east-northeast. At this point it had multiple vortices embedded in the overall wedge shaped tornado. The strongest of these vortices appears to have scoured the ground and left broad circulation patterns of debris in the overall damage and debris field. Around this time the tornado likely became wrapped in heavy rain and would have been difficult to observe from a distance. The most extreme damage appeared to be in the northeast corner of the community.||Northwood, in southwest Grand Forks County, had a population of about 1000 people. 90 percent of the roughly 460 homes were damaged. One death occurred in a mobile home, with 18 other injuries reported. The death occurred in a trailer park on the north edge of town, where 19 total units were demolished.||Just to the east of the trailer park, in the area that sustained the extreme damage, three businesses were hit particularly hard. An agricultural company, the towns largest employer, had its buildings heavily damaged. A nearby construction company lost two large steel buildings and other equipment. Steel beams from the two steel buildings were twisted and tossed nearby. Finally, a car dealership lost 15 to 20 vehicles from its parking lot along highway 15. Many of these vehicles were damaged beyond recognition and tossed into nearby fields. One corn field to the north of highway 15 (across from the 3 businesses on the northeast side of town) had it stalks snapped off several inches from the root bases, with pieces of husked corn laying around.||Hangers and airplanes were also damaged at the airport. The local health center, school, supermarket, and grain elevator were damaged. Near the elevator, several rail cars were knocked off the tracks. Hundreds of trees were snapped, uprooted, or damaged. Power was also knocked out to many customers, but eventually was turned off (for safety reasons) to the entire town. A total of about 2600 truckloads of debris were hauled to the town landfill. In the days following the tornado, a Presidential Disaster Declaration was granted.

The deaths

1 direct deaths are recorded for this tornado, each with what Storm Data knows of it.

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

14 minutes of warning. NWS FGF issued a tornado warning for this county at 00:50 UTC, 14 minutes before the tornado touched down, in force until 01:45 UTC.

The county was under a tornado watch, issued at 22:10 UTC and running to 01:51 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 00:53 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 Fargo/Grand Forks radar (KMVX), 52 km away, was scanning. The volume nearest the touchdown began at 01:02 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 2007 tornado in North DakotaEvery tornado in North Dakota since 1950Warnings in force in North Dakota nowThe forecast where you are

10 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.