Isolated strong thunderstorms formed across portions of Richland and Cass counties during the early morning hours of the 29th. These storms produced very large hail. Several hours later a line of thunderstorms approached the New Rockford, North Dakota, area, and began to bow, which is indicative of strong winds. This bowing signature on radar continued as the line of thunderstorms tracked eastward along U. S. Highway 2 toward the Grand Forks (ND) and Oslo (MN) areas, where they gradually weakened.

Hail in RICHLAND, NORTH DAKOTA
From 29-AUG-13 01:15:00 to 29-AUG-13 01:15:00 (CST-6)
Location: WALCOTT
Magnitude: 1.25 
Reported by: Public

Hail from nickel to half dollar size occurred across the northwest corner of Colfax West Township.

Hail in RICHLAND, NORTH DAKOTA
From 29-AUG-13 01:25:00 to 29-AUG-13 01:25:00 (CST-6)
Location: WALCOTT
Magnitude: 2.50 
Reported by: Broadcast Media

Hail up to tennis ball size fell in and around Walcott.

Hail in CASS, NORTH DAKOTA
From 29-AUG-13 02:52:00 to 29-AUG-13 02:52:00 (CST-6)
Location: CASSELTON
Magnitude: 1.00 
Reported by: Broadcast Media

Dime to quarter size hail fell north of Casselton.

Thunderstorm Wind in RAMSEY, NORTH DAKOTA
From 29-AUG-13 05:00:00 to 29-AUG-13 05:00:00 (CST-6)
Location: DOYON
Magnitude: 60.00 EG
Reported by: Public

Numerous large tree branches were broken in and near Doyon. The grandstands were flipped and a travel trailer tumbled at the Devils Lake Speedway.

Thunderstorm Wind in NELSON, NORTH DAKOTA
From 29-AUG-13 05:10:00 to 29-AUG-13 05:10:00 (CST-6)
Location: LAKOTA
Magnitude: 55.00 EG
Reported by: Law Enforcement

Several four to eight inch diameter tree branches were broken down around Lakota.

Thunderstorm Wind in NELSON, NORTH DAKOTA
From 29-AUG-13 05:20:00 to 29-AUG-13 05:20:00 (CST-6)
Location: MICHIGAN CITY
Magnitude: 55.00 EG
Reported by: Law Enforcement

Several four to eight inch diameter tree branches were blown down in Michigan.

Thunderstorm Wind in WALSH, NORTH DAKOTA
From 29-AUG-13 06:05:00 to 29-AUG-13 06:05:00 (CST-6)
Location: FOREST RIVER
Magnitude: 50.00 EG
Reported by: Public

A few large tree branches were blown down in a farm shelterbelt.

Thunderstorm Wind in GRAND FORKS, NORTH DAKOTA
From 29-AUG-13 06:15:00 to 29-AUG-13 06:15:00 (CST-6)
Location: MANVEL
Magnitude: 50.00 EG
Reported by: NWS Storm Survey

Large tree branches were blown down in a shelterbelt.

Thunderstorm Wind in WALSH, NORTH DAKOTA
From 29-AUG-13 06:15:00 to 29-AUG-13 06:15:00 (CST-6)
Location: POLAND
Magnitude: 50.00 EG
Reported by: NWS Storm Survey

Several large cottonwood trees were snapped in a shelterbelt.

Thunderstorm Wind in EDDY, NORTH DAKOTA
From 29-AUG-13 04:30:00 to 29-AUG-13 04:30:00 (CST-6)
Location: NEW ROCKFORD
Magnitude: 52.00 EG
Reported by: Law Enforcement

The strong winds caused a car to shake violently.

Thunderstorm Wind in GRAND FORKS, NORTH DAKOTA
From 29-AUG-13 05:30:00 to 29-AUG-13 05:30:00 (CST-6)
Location: NIAGARA
Magnitude: 52.00 EG
Reported by: Public

Very strong winds and rain were reported with a few large tree branches torn down around town.

Hail in CASS, NORTH DAKOTA
From 29-AUG-13 02:30:00 to 29-AUG-13 02:30:00 (CST-6)
Location: LYNCHBURG
Magnitude: 1.25 
Reported by: Public