You've got to see to believe this video of a surprise tornado shot by a viewer in Longmont on Monday.

John Traxinger says he was near Heather Hill Circle and Renaissance Dr., at 2:27 p.m. when he saw what looked like a tornado, and shot some video on his cell phone.

It appears to be a landspout tornado. You can't actually tell from the video if it is attached to a cloud base or not, so it is hard to say for sure. If it is attached, it would be called a landspout. If it was not attached, it would be called a gustnado.

Wind shear and gusty winds below a storm can cause an updraft or a column of air to start rotating. These are not traditional supercell tornadoes that are caused by the actual rotation of a strong thunderstorm. Supercell tornadoes are much more violent.

Judging by the thin appearance of the vortex and the little amount of debris being pulled up, the winds right there on the ground nearby this Longmont tornado, was probably between 60-70 mph.

No damage or tornadoes were reported to the National Weather Service. Traxinger probably didn't report the tornado because he wasn't sure what it was. Landspout tornadoes are usually very short-lived as well, only lasting about 5 or 10 minutes. No length of time was reported to 9NEWS with this one.

Either way, it's a very cool video.

Remember, tornadoes are not severe weather. Only hail larger than 1 inch, and wind gusts greater than 58 mph, are considered severe weather.

It is quite common in Colorado for tornadoes to form from thunderstorms that are no where near severe.

There were no severe thunderstorm, or tornado warning issued in Colorado on Monday.

Cory Reppenhagen is the newest member of the 9NEWS Weather Team. Follow him on Twitter here