Pictures posted on social media by Callum Beag Macleod show the scale of the 'twister' above Clisham, a mountain in Harris.
Callum told The Scotsman: "It just lasted about 10 minutes tops, moving in a westerly direction.
"I took the photos from my garden with a phone camera on full zoom as it was probably about 10 miles from me. I was enjoying bright sunshine at the time."
Callum took the pictures on Saturday afternoon and has seen them shared over 300 times on Facebook.
The Met Office has even used the images on their website, while many others have been reacting on social media and sharing their own pictures of the twister.
One social media user, Dolina Johnson, wrote: "What! Is this real?"
Callum replied: "Yes, real! No sign of Clisham now!"
Another, Rhoda Bain, said: "Wow! That's impressive."
Popular Western Isles band Peat & Diesel have also posted a Twitter link of the image with the caption: "Band practice got a little out of hand yesterday..."
The Met Office website says a tornado is a rapidly rotating column of air that reaches between the base of a storm cloud and the Earth's surface, forming in very unsettled weather conditions as part of thunderstorms.
Descending currents of cold, dense air within the supercell storm help to concentrate the rotation and bring it down to lower levels. Evenutally, the rotation may become so strongly-focused that a narrow column of violently rotating air forms.
By the Met Office definition, once this violently-rotating column of air reaches the ground a tornado is born.
Tornadoes occur in many places around the world but North America is the continent where they're seen most often.