A tornado that touched down in South Dakota last weekend was extremely rare because it was rotating clockwise, the opposite of most twisters in the Northern Hemisphere.

How rare is it? About 1% of tornadoes in the Northern Hemisphere rotate clockwise, according to the National Weather Service in Aberdeen, South Dakota.

This rare tornado was on the ground for about 45 seconds and was rated EF0. It was the first tornado to touch down in South Dakota so far this year, according to NOAA's Storm Prediction Center.

The twister's peak winds were estimated at 75 mph. Seven trees were knocked down.

credit: Sean Kathy Lesnar via Facebook