EF0 tornado in Sioux County, North Dakota

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.

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.