MONROE — Weather officials are confident a tornado touched down in Green County this week, they just are not having a lot of luck classifying its strength.
Nonetheless, officials are confident that some kind of twister struck around 6:08 p.m. on Monday, Sept. 25, east of New Glarus and just south of Belleville, amid storms that evening.
The National Weather Service (NWS) is reviewing pictures and reports from the area to classify the tornado that evidence suggests touched down in a field, said Taylor Patterson, a meteorologist with the NWS office at Sullivan near Milwaukee.
There was not a tornado warning issued for this storm, as it moved swiftly through the area.
Tornadoes are measured using the Enhanced Fujita Scale that measures the strength of tornadic winds. The scale ranges from EF0 to EF5, lower is weaker and higher is strongest, but at this point, they are calling the state’s most recent tornado an “EFU” — “U” for unknown.
On Thursday, Patterson said the service was allowing another day or two for residents to submit evidence of the Green County tornado’s strength — pictures of damage to structures, fields, and trees.
“It’s all based on that sort of evidence,” said Patterson. “When it doesn’t do any damage that’s fortunate, but it doesn’t help us,” measure the tornado’s strength.
And whereas in some regions of the country tornadoes occur in clusters or outbreaks, the tornado in Green County appears to have been an isolated event.
“When we are dealing with storms in Wisconsin, it’s not unusual for a storm to produce a single tornado and be done,” she said. “We are not in an environment where we get multiple or long-track tornadoes.”
So far this year, Wisconsin has seen 20 tornadoes. The total for 2022 was 28 tornadoes. None of the 2023 twisters in the state surpassed the EF1 classification, in which winds speeds range from 65 to 85 mph — still enough to produce damage to structures, trees and fields.
Patterson said last Monday’s storm was reminiscent of a similar storm that hit roughly the same area in October 2022. The deadliest tornado in Wisconsin history occurred way back on June 12, 1899 in New Richmond, St. Croix County. That twister killed 117.
On June 8, 1984, a monster EF5 tornado struck Barneveld in Dane County near Blue Mounds. That twister came in the middle of the night and destroyed about 90% of the town. In an EF5, the winds exceed a devastating 200 mph.