A surface warm front continued to lift slowly north across southern North Dakota during the day on Monday, May 24th, in advance of a potent upper level trough racing northeast across the Rocky Mountains and towards the Northern Plains.  Tornado Watch number 215 was issued by mid afternoon in anticipation of rapid thunderstorm development and intensification once mass divergence associated with the upper wave spread across the region. An elevated threat for tornadoes existed along the warm front due to favorable low level vertical shear parameters.
Numerous severe thunderstorm and tornado warnings were issued from late in the afternoon till later in the evening.  Several reports of large hail, multiple reports of severe thunderstorm winds, and several reports of funnel clouds and tornadoes were received during this event. The number of confirmed tornadoes was two.

Hail in MORTON, NORTH DAKOTA
From 24-MAY-10 17:54:00 to 24-MAY-10 18:01:00 (CST-6)
Location: HEBRON
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Thunderstorm Wind in GRANT, NORTH DAKOTA
From 24-MAY-10 16:00:00 to 24-MAY-10 16:15:00 (MST-7)
Location: NEW LEIPZIG
Magnitude: 74.00 EG
Property damage: 60.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

Straight line winds associated with a severe thunderstorm destroyed two outbuildings on a farm.  The wind speed was estimated based on the damaged observed during a storm survey.

Thunderstorm Wind in GRANT, NORTH DAKOTA
From 24-MAY-10 16:20:00 to 24-MAY-10 16:27:00 (MST-7)
Location: CARSON
Magnitude: 70.00 EG
Property damage: 30.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

Strong straight line winds associated with a severe thunderstorm resulted in several large evergreen and cottonwood trees to become uprooted or were blown over. The wind speed was estimated from a storm survey.

Thunderstorm Wind in ADAMS, NORTH DAKOTA
From 24-MAY-10 16:37:00 to 24-MAY-10 16:42:00 (MST-7)
Location: HETTINGER
Magnitude: 53.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

Thunderstorm Wind in STUTSMAN, NORTH DAKOTA
From 24-MAY-10 17:37:00 to 24-MAY-10 17:42:00 (CST-6)
Location: JAMESTOWN
Magnitude: 53.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

Thunderstorm Wind in MORTON, NORTH DAKOTA
From 24-MAY-10 17:50:00 to 24-MAY-10 18:05:00 (CST-6)
Location: ALMONT
Magnitude: 70.00 EG
Property damage: 80.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

Strong straight line winds associated with a severe thunderstorm tore the roof off of a farm outbuilding, broke off tree branches, blew down a small wind turbine, and pushed a large old barn so that it now leans towards the north. Wind speed was estimated from the visual inspection of damage during a storm survey.

Thunderstorm Wind in WELLS, NORTH DAKOTA
From 24-MAY-10 20:30:00 to 24-MAY-10 20:45:00 (CST-6)
Location: CHASELEY
Magnitude: 70.00 EG
Property damage: 20.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Strong winds associated with a severe thunderstorm caused some damage to a home.

Funnel Cloud in HETTINGER, NORTH DAKOTA
From 24-MAY-10 15:19:00 to 24-MAY-10 15:21:00 (MST-7)
Location: NEW ENGLAND
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Two funnel clouds were reported along Highway 22 south of New England.

Thunderstorm Wind in HETTINGER, NORTH DAKOTA
From 24-MAY-10 15:30:00 to 24-MAY-10 15:40:00 (MST-7)
Location: MOTT
Magnitude: 52.00 EG
Property damage: 20.00K
Crop damage: 0.00K
Reported by: COOP Observer

Severe thunderstorm wind gusts resulted in shingle damage to a home and three to five inch diameter trees broken.

Thunderstorm Wind in MCINTOSH, NORTH DAKOTA
From 24-MAY-10 17:00:00 to 24-MAY-10 17:15:00 (CST-6)
Location: ASHLEY
Magnitude: 70.00 EG
Property damage: 50.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Strong straight line winds associated with a severe thunderstorm resulted in damage to farm outbuildings.

Hail in DICKEY, NORTH DAKOTA
From 24-MAY-10 17:15:00 to 24-MAY-10 17:21:00 (CST-6)
Location: ELLENDALE
Magnitude: 1.25 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Hail in MORTON, NORTH DAKOTA
From 24-MAY-10 17:54:00 to 24-MAY-10 18:01:00 (CST-6)
Location: GLEN ULLIN
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Thunderstorm Wind in WELLS, NORTH DAKOTA
From 24-MAY-10 20:30:00 to 24-MAY-10 20:45:00 (CST-6)
Location: HURDSFIELD
Magnitude: 61.00 EG
Property damage: 20.00K
Crop damage: 0.00K
Reported by: Public

Strong winds associated with a severe thunderstorm blew over a semi trailer near Hurdsfield.

Thunderstorm Wind in WELLS, NORTH DAKOTA
From 24-MAY-10 20:36:00 to 24-MAY-10 20:51:00 (CST-6)
Location: HARVEY
Magnitude: 70.00 EG
Property damage: 200.00K
Crop damage: 0.00K
Reported by: Newspaper

Very strong winds associated with a severe thunderstorm damaged a building at the Harvey airport and also blew over numerous trees and some power lines.  Other structural damage was also sustained in and around the Harvey area.

Thunderstorm Wind in BURLEIGH, NORTH DAKOTA
From 24-MAY-10 19:53:00 to 24-MAY-10 19:58:00 (CST-6)
Location: MOFFIT
Magnitude: 55.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: RAWS

Peak thunderstorm wind gust reported at the Long Lake National Wildlife Refuge.

Thunderstorm Wind in PIERCE, NORTH DAKOTA
From 24-MAY-10 20:58:00 to 24-MAY-10 21:08:00 (CST-6)
Location: BALTA
Magnitude: 56.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Employee

Very heavy rain accompanied the severe thunderstorm winds.

Thunderstorm Wind in BURLEIGH, NORTH DAKOTA
From 24-MAY-10 19:47:00 to 24-MAY-10 19:58:00 (CST-6)
Location: ARENA
Magnitude: 78.00 EG
Property damage: 400.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

A farmstead two miles east of Arena sustained heavy damage from severe thunderstorm straight line winds. One outbuilding was destroyed, a television antenna was blown down, roof damage was sustained to the home and another outbuilding, and several trees had damage. The severity of the damage was indicative of winds up to 90 miles per hour.

Thunderstorm Wind in MORTON, NORTH DAKOTA
From 24-MAY-10 18:00:00 to 24-MAY-10 18:08:00 (CST-6)
Location: FLASHER
Magnitude: 50.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Numerous tree branches were blown down in Flasher from severe thunderstorm wind gusts.

Thunderstorm Wind in OLIVER, NORTH DAKOTA
From 24-MAY-10 18:21:00 to 24-MAY-10 18:27:00 (CST-6)
Location: CENTER
Magnitude: 50.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Very heavy rain accompanied the strong thunderstorm winds.

Thunderstorm Wind in EMMONS, NORTH DAKOTA
From 24-MAY-10 19:51:00 to 24-MAY-10 19:59:00 (CST-6)
Location: STRASBURG
Magnitude: 56.00 EG
Property damage: 20.00K
Crop damage: 0.00K
Reported by: Mesonet

Twenty inch in diameter trees were reported blown down from severe thunderstorm wind gusts.

Hail in STARK, NORTH DAKOTA
From 24-MAY-10 16:05:00 to 24-MAY-10 16:14:00 (MST-7)
Location: LEFOR
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

No damage was reported.

Thunderstorm Wind in LOGAN, NORTH DAKOTA
From 24-MAY-10 20:00:00 to 24-MAY-10 20:20:00 (CST-6)
Location: NAPOLEON
Magnitude: 78.00 EG
Property damage: 500.00K
Crop damage: 100.00K
Reported by: Newspaper

There was significant damage to farms from about six miles west of Napoleon to about two miles northwest of Napoleon. Damage was done to pole barns and other outbuildings. Six power poles were snapped and one cow was killed in the area west of Napoleon. There was also crop damage.

Tornado in SIOUX, NORTH DAKOTA
From 24-MAY-10 16:05:00 to 24-MAY-10 16:10:00 (MST-7)
Location: SELFRIDGE
Tornado F-scale: EF1
Property damage: 25.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

A tornado touched down in western Sioux County and crossed into southwest Grant County. Damage was sustained to a roof on a farmstead in Sioux County. Based on a storm survey of the area damage was consistent with a low end EF1 tornado. From that it was determined that wind speeds were around 90 mph. The tornado crossed into Grant County. See the tornado entry for Grant County.

Thunderstorm Wind in LA MOURE, NORTH DAKOTA
From 24-MAY-10 17:10:00 to 24-MAY-10 17:25:00 (CST-6)
Location: EDGELEY
Magnitude: 91.00 EG
Property damage: 1.00M
Crop damage: 0.00K
Reported by: Emergency Manager

Extreme straight line winds associated with a severe thunderstorm caused extensive damage north of Kulm. Visual inspection of storm survey photos indicate estimated winds of 90 to 105 mph.  The worst damage and highest estimated winds occurred roughly 2 miles north-northwest of Kulm where 4 large grain bins were destroyed and heavy damage was sustained to a shop on a farmstead. Also, one wall was destroyed and the roof collapsed on a large machine shed, and several pieces of farm machinery had damage from being blown over. Preliminary damage estimates indicated one million dollars to this one location. Other areas north of Kulm also sustained damage from the straight line wind gusts, but not as severe.

Thunderstorm Wind in SHERIDAN, NORTH DAKOTA
From 24-MAY-10 20:30:00 to 24-MAY-10 20:50:00 (CST-6)
Location: MARTIN
Magnitude: 70.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Public

There was damage to an outbuilding on a farm and to trees. Heavy rain accompanied the strong thunderstorm winds.

Thunderstorm Wind in LA MOURE, NORTH DAKOTA
From 24-MAY-10 17:10:00 to 24-MAY-10 17:25:00 (CST-6)
Location: JUD
Magnitude: 78.00 EG
Property damage: 100.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Extreme straight line winds associated with a severe thunderstorm caused extensive damage north of Kulm. Visual inspection of storm survey photos indicate estimated winds of 90 to 105 mph.  The strong winds blew off the sheet metal on a building on this farmstead.

Thunderstorm Wind in LA MOURE, NORTH DAKOTA
From 24-MAY-10 17:10:00 to 24-MAY-10 17:25:00 (CST-6)
Location: JUD
Magnitude: 78.00 EG
Property damage: 250.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Extreme straight line winds associated with a severe thunderstorm caused extensive damage north of Kulm. Visual inspection of storm survey photos indicate estimated winds of 90 to 105 mph.  Four farmsteads in this area had damage. Damage included farm machinery tipped over, damage to grain bins, and a few farm outbuildings destroyed.

Tornado in SIOUX, NORTH DAKOTA
From 24-MAY-10 18:09:00 to 24-MAY-10 18:13:00 (MST-7)
Location: FT YATES
Tornado F-scale: EF0
Property damage: 5.00K
Crop damage: 0.00K
Reported by: COOP Observer

This tornado was not reported to the National Weather Service in real time. It was determined, based on information gathered, that this tornado formed north-northwest of Fort Yates, and moved northeast. There were no injuries. Reports indicate very minor damage to fences and a trailer home. There were no injuries. From that it was determined that this was an EF0 tornado with wind speeds then estimated, based on the EF Scale, at about 70 mph.

Thunderstorm Wind in BURLEIGH, NORTH DAKOTA
From 24-MAY-10 19:44:00 to 24-MAY-10 19:51:00 (CST-6)
Location: WING
Magnitude: 74.00 EG
Property damage: 50.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Damage was reported near Wing from severe thunderstorm wind gusts. Several trees and power lines were blown down, along with damage to a deck on a home.

Hail in BURLEIGH, NORTH DAKOTA
From 24-MAY-10 19:24:00 to 24-MAY-10 19:29:00 (CST-6)
Location: (BIS)BISMARCK MUNI A
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Thunderstorm Wind in BURLEIGH, NORTH DAKOTA
From 24-MAY-10 19:53:00 to 24-MAY-10 19:58:00 (CST-6)
Location: DRISCOLL
Magnitude: 56.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Storm Chaser

Flash Flood in STUTSMAN, NORTH DAKOTA
From 24-MAY-10 17:35:00 to 24-MAY-10 19:30:00 (CST-6)
Location: JAMESTOWN
Flood cause: Heavy Rain
Property damage: 50.00K
Crop damage: 0.00K
Reported by: Newspaper

Flash flooding was reported in and around the Jamestown area due to very heavy thunderstorm rains. Several streets had several feet of water and minor damage was done to buildings by flood waters. Some county roads outside the city had water over them. Significant damage was not reported.

Thunderstorm Wind in KIDDER, NORTH DAKOTA
From 24-MAY-10 20:24:00 to 24-MAY-10 20:30:00 (CST-6)
Location: TAPPEN
Magnitude: 56.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Heavy rain accompanied the strong winds.

Thunderstorm Wind in MORTON, NORTH DAKOTA
From 24-MAY-10 18:15:00 to 24-MAY-10 18:45:00 (CST-6)
Location: NEW SALEM
Magnitude: 83.00 EG
Property damage: 1.30M
Crop damage: 0.00K
Reported by: NWS Storm Survey

A large fertilizer building north of New Salem sustained heavy damage from extreme straight line winds associated with a severe thunderstorm. Visual inspection of the damage conducted during a storm survey indicates estimated winds of 95 mph. Much of the damage was to the roof of the building, in which much of the metal roof was peeled back and blown off to the north. Preliminary damage was estimated at over one million dollars to the building and loss of fertilizer.
Additional damage from severe thunderstorm winds was observed north-northeast of New Salem towards the Morton County and Oliver County border. Several farms had damage to outbuildings, trees, and farm equipment.  Damage here was estimated at one quarter of a million dollars.

Thunderstorm Wind in EMMONS, NORTH DAKOTA
From 24-MAY-10 19:40:00 to 24-MAY-10 19:59:00 (CST-6)
Location: LINTON
Magnitude: 70.00 EG
Property damage: 90.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Strong winds associated with a severe thunderstorm resulted in moderate damage within the city of Linton. Parts of the roof were torn off of the Linton fire hall and several trees were blown down. Reports of damage to other roofs in Linton and several power lines blown down were also received.

Thunderstorm Wind in BURLEIGH, NORTH DAKOTA
From 24-MAY-10 19:35:00 to 24-MAY-10 20:05:00 (CST-6)
Location: DRISCOLL
Magnitude: 74.00 EG
Property damage: 200.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

A farmstead one mile west of Driscoll sustained damage to two outbuildings. Tree damage was evident from just north of Driscoll, northward to Arena. A farmstead five miles south of Arena had one outbuilding damaged.  The damage was indicative of severe thunderstorm straight line winds up to 85 miles per hour.

Thunderstorm Wind in KIDDER, NORTH DAKOTA
From 24-MAY-10 20:00:00 to 24-MAY-10 20:11:00 (CST-6)
Location: TUTTLE
Magnitude: 65.00 EG
Property damage: 55.00K
Crop damage: 0.00K
Reported by: Mesonet

Severe thunderstorm wind gusts damaged a shed and destroyed a garage.

Tornado in GRANT, NORTH DAKOTA
From 24-MAY-10 16:10:00 to 24-MAY-10 16:15:00 (MST-7)
Location: NEW LEIPZIG
Tornado F-scale: EF1
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

This tornado crossed into southwest Grant County from western Sioux County. See the tornado entry for Sioux County. The tornado hit no structures in Grant County, but did do damage in Sioux County. It was rated low end EF1 with estimated winds of 90 mph.

Tornado in KIDDER, NORTH DAKOTA
From 24-MAY-10 20:00:00 to 24-MAY-10 20:10:00 (CST-6)
Location: TUTTLE
Tornado F-scale: EF1
Property damage: 250.00K
Crop damage: 0.00K
Reported by: Public

The public reported damage to farms in the area. Most of the damage was caused by thunderstorm winds, however, the damage in one area was descriptive of a tornado. The farmer with the worst damage described objects scattered about in east, north, northwest, and west directions. His description of the debris field indicated that this was likely a tornado. Vehicles were damaged, along with garages, stalls, and barns. Trees were uprooted. One garage was blown to the west, while animal feeders were blown to the east. Based on the description of damage it was determined that this was an EF1 tornado. From that the estimated wind speed was around 100 mph.

Thunderstorm Wind in LA MOURE, NORTH DAKOTA
From 24-MAY-10 17:10:00 to 24-MAY-10 17:25:00 (CST-6)
Location: JUD
Magnitude: 78.00 EG
Property damage: 150.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Extreme straight line winds associated with a severe thunderstorm caused extensive damage north of Kulm. Visual inspection of storm survey photos indicate estimated winds of 90 to 105 mph.  The strong winds blew off the sheet metal on a barn, did damage to a garage wall, snapped some trees, and bent metal on a shop on this farmstead.