The region of the United States from North Dakota eastward to Michigan has more cold core funnel clouds than anywhere else in the country. Cold core funnels, commonly called "cold air funnels" are condensation funnels that form in and around weak convective showers. Because the updrafts within these showers are not nearly an intense as those found in supercell thunderstorms, there is less energy available for rotation. Cold core funnels usually do not reach the ground and if they do, they usually do not do much damage.
Most of the time, these weak rotations produce wind speeds like those in a dust devil rather than a tornado. However, there can be hybrid situations in which a cold core funnel does become strong when its parent shower grows stronger. Cold core funnels are usually small and not too scary-looking, but should always be reported to weather media, law enforcement, or the National Weather Service.