Severe storms that popped up around North Dakota late Friday spawned multiple tornadoes in the south central part of the state, including north of Bismarck, prompting warning sirens.

The National Weather Service confirmed nine tornadoes in a 3 ½-hour span Friday.

The cluster of tornado touchdowns in the region wasn't due to any particular factor, but it was somewhat unusual, according to Weather Service Meteorologist Megan Jones.