For about a minute, a tornado touched down in an open field on Feb. 24 southeast of Watertown in Codington County, the first time a tornado was documented in February in South Dakota history.

The National Weather Service reported that the “brief, weak” tornado touched the ground shortly after 4 p.m. near the borders of Codington, Hamlin and Deuel counties. The conditions weren’t suitable for strong thunderstorms, but there was just enough low-level rotation for the tornado to form, the weather service said.

The tornado didn’t last long and no damage was observed, which means it will be ranked EF-U – for unknown – on the Enhanced Fujita scale used to measure tornado intensity.

The only remaining months without a recorded tornado in South Dakota are November, December and January, the weather service said. The state has had more than 1,900 documented tornadoes, but this was the first one to happen during winter, according to The Weather Channel.

The tornado followed a major shift in temperature across the region, with highs reaching the 50s and 60s only days after wind chills were well below zero. For example, Aberdeen recorded a record-high temperature of 64 degrees on Feb. 23, five days after the 7 a.m. wind chill was recorded at 43 below zero, the National Weather Service said in an X post.

With spring and summer approaching, the possibility of severe weather will be more prevalent. Here’s what you need to know to be prepared.

What’s the difference between a tornado watch and a tornado warning?

The National Weather Service has different types of alerts for tornadoes depending on the situation.

• Tornado watch: A watch means tornadoes are possible in and near the watch area. When a watch is issued, it means to be ready to act quickly if you suspect a tornado is approaching.
• Tornado warning: A warning means a funnel cloud or tornado has been sighted or seen on weather radar. It’s time to move to an interior room on the lowest floor of a sturdy building and avoid windows. A warning typically covers a much smaller area than a watch.
• Tornado emergency: An emergency indicates that a violent tornado has touched down in the area, and it’s a severe threat to life and property, with catastrophic damage already confirmed. It’s time to immediately seek shelter and notify family or friends in the area to be sure they are aware of the situation.

How is the intensity of tornadoes measured?

The Enhanced Fujita scale is used to give tornadoes a rating based on estimated wind speeds and related damage. 

• EF-0: The tornado has winds between 65 mph and 85 mph. It’s the weakest classification and these tornadoes do minor damage.
• EF-1: These tornadoes have wind speeds between 86 mph and 110 mph and cause moderate damage.
• EF-2: These tornadoes have wind speeds of 111 mph and 135 mph and cause considerable damage.
• EF-3: These tornadoes have wind speeds of 136 mph and 165 mph and cause severe damage.
• EF-4: These tornadoes have wind speeds of 166 mph and 200 mph and cause devastating damage.
• EF-5: These tornadoes have wind speeds above 200 mph and cause incredible damage.