EF1 tornado in Dickey County, North Dakota

A National Weather Service storm survey confirmed that an EF1 tornado on the Enhanced Fujita Scale briefly touched down five miles northwest of Merricourt. There was an eye witness to the tornado. A pole barn was damaged along with numerous trees snapped. The damage corresponded to low end EF1 on the Enhanced Fujita Scale. From that it was determined that wind speeds were on the order of 90 miles per hour.

A strong upper level jet streak moving into the region triggered scattered elevated thunderstorm activity during the late morning hours of July 10th over southwest North Dakota. Large hail up to two inches in diameter was reported with these storms. As the aerial coverage of storms became more widespread, Severe Thunderstorm Watch number 616 was issued. Once the storms advected to the east into south central and southeast North Dakota during the afternoon, they became rooted in the boundary layer and became much more intense necessitating the issuance of Tornado Watch number 617. Considerable veering winds with height, strong instability, and favorable deep layer sheer produced a favorable environment for very large hail, damaging winds, and isolated tornadoes.

Multiple severe thunderstorm warnings and several tornado warnings were issued during this event. Numerous reports of large hail and destructive thunderstorm winds were received. After in depth investigation including two separate storm damage surveys, it was concluded that four confirmed tornadoes occurred during this event, including EF2 tornado damage seven miles south of Napoleon.