Weather tracker: Tornado outbreak shatters North Dakota's yearly record

"The yearly tornado record in North Dakota was shattered in just a few hours as the state experienced an extraordinary weather event. More than 20 tornadoes tore through South Dakota and North Dakota, with the storm system stretching across a 200-mile area, according to the National Weather Service. Since 1995, the annual average for the state was 29 tornadoes, with the peak season occurring in June and July."

"However, last weekend's intense outbreak pushed the total to a staggering 73, surpassing the previous record of 61, set in 1999. The tornadoes first touched down in Mobridge, South Dakota, where they caused significant damage, flipping vehicles and downing power lines. Meanwhile, the North Dakota capital, Bismarck, received heavy rainfall from the same storm system, with more than 50mm in less than an hour. Streets were flooded and vehicles stranded as the city experienced its wettest September in 31 years."

"A rare atmospheric setup created the perfect conditions for tornado formation, with a low-pressure system, low-wind shear and a warm front aligning to fuel the storms. As the day wore on, the tornadoes weakened but the storm system brought moisture and warmth from the North Pacific Ocean, which added extra energy to the atmosphere and increased the likelihood of tornado formation across the Northern Plains."

An intense storm system produced more than 20 tornadoes across South Dakota and North Dakota, stretching roughly 200 miles and driving the state total to 73 tornadoes. The outbreak shattered the previous record of 61 set in 1999 and far exceeded the long-term annual average of 29 tornadoes. Tornadoes caused significant damage in Mobridge, South Dakota, flipping vehicles and downing power lines. The same system delivered heavy rainfall to Bismarck, causing rapid flooding and producing the wettest September in 31 years with 61.9mm of rain. A rare atmospheric setup and additional Pacific moisture fueled the outbreak. Tropical Storm Gabrielle formed in the central Atlantic but posed no immediate threat to land.

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