EF3 tornado, San Haven to Rocklake, North Dakota, July 7, 2008

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

July 7, 2008

Touchdown

2:50 PM CDT (19:50 UTC)

Lifted

3:50 PM CDT (20:50 UTC)

On the ground

60 minutes

Path length

20.6 miles (33.1 km)

Path width

250 yards (229 m)

Deaths

0

Injuries

3

Property damage

$1.5 million

Crop damage

$5,000

Counties

Rolette and Towner counties

Touchdown point

48.852, -99.917

Lift-off point

48.841, -99.453

Record number

0807071350-01

In the early afternoon hours of Monday, July 7th, isolated thunderstorms developed over southwestern Manitoba, Canada, as a result of an upper level short wave trough tracking east across south central Canada. Maximized low level wind shear along a surface boundary over north central North Dakota, along with low lifted condensation levels, created a favorable environment for low level mesocyclones and the development of isolated tornadoes.||The end result was a tornadic supercellular thunderstorm developing near Lake Metigoshe. It tracked east-southeast through northeastern Bottineau County and across northern Rolette County, before exiting into Towner County (Grand Forks, North Dakota County Warning Area) later in the afternoon. A storm survey conducted the following day found tornado damage in the Belcourt and Rolla areas, with the heaviest damage observed on the north side of Rolla. There were injuries from the tornadoes, but there were no deaths. Estimated damage was around one and a half million dollars.

An area of low pressure moved along the Canadian border on Monday (7th) and developed several severe thunderstorms. A triple point, or the intersection of multiple boundaries, formed in north central North Dakota, and resulted in several tornado reports.

By North Dakota standards this was a long lived tornado that covered many miles.||A National Weather Service storm damage survey was completed in Rolette County on July 8, the day following the event. The storm survey concluded that the total path length was 17.6 miles, with a maximum width of 250 yards. The worst damage corresponded to low end EF3 on the Enhanced Fujita Scale, with maximum estimated winds of 140 mph. ||Multiple tornado sightings were reported by local officials and residents along Bureau of Indian Affairs (BIA) Highway number eight between 2:50 PM CDT and 3:10 PM CDT. The storm survey concluded that tree and structural damage along this corridor west and northwest of Belcourt corresponded to EF1 and EF2 on the Enhanced Fujita scale, or wind speeds ranging from 90 to 130 mph, with a path width ranging from 50 to 75 yards. Greater damage was surveyed north and northeast of Belcourt. Along BIA Highway number seven, a tornado path width of 250 yards was observed with significant widespread tree damage, corresponding to an EF2 rating or winds of 115 to 130 mph. Northeast of Belcourt along BIA highway number five, a home sustained heavy damage and there was one injury. Here, a rating of EF2 was assigned, with estimated wind speeds up to 135 mph. Storm reports around the immediate Belcourt area indicate a time of approximately 3:15 PM CDT for tornado impact. Seventy structures in total were impacted in the Belcourt area with varying degrees of damage.||The tornadic storm continued east hitting the north side of the city of Rolla at approximately 3:30 PM CDT. Twelve homes were destroyed and 18 homes were damaged. The homes with the most significant structural damage corresponded to an EF3 rating. From this it was determined that the maximum wind speeds here were on the order of 140 mph. Two minor injuries were also reported in the Rolla area. The tornado continued east-southeast, hitting a farmstead east of Rolla which sustained structural and tree damage consistent with an EF2 tornado, or winds around 125 mph. The tornado then crossed US Highway 281 before pushing southeast into Towner County (See National Weather Service Grand Forks, North Dakota Storm Data from July 7, 2008).

This tornado originated in Rolette County, where it produced EF3 damage near Rolla. It continued into Towner County for about 3 more miles and lifted about 11 miles west-northwest of Rock Lake. It produced mainly EF1 damage to scattered trees and fields in Towner County. Peak winds in Towner County were estimated at 90 mph.

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

14 minutes of warning. NWS BIS issued a tornado warning for this county at 19:36 UTC, 14 minutes before the tornado touched down, in force until 20:00 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 General Thunderstorms Risk. The outlook in force was issued at 16:28 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.

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 2008 tornado in North DakotaEvery tornado in North Dakota since 1950Warnings in force in North Dakota nowThe forecast where you are

7 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.