Many areas of Scotland have been experiencing an unusual meteorological phenomenon known as thundersnow.

Thundersnow is when heavy snowfall is accompanied by thunder and lightning, unlike a regular thunderstorm where the thunder and lighting is accompanied by rain.

It is rare in Scotland, and normally the most likely place to experience it being in the Northern Isles. However, recent days have seen reports of it in the Perth and Dundee areas, as well as in Aberdeen and Inverness.

STV weather presenter Sean Batty explained what was causing it, saying: "The air, which is extremely cold, has come off the continent and travelled across the North Sea picking up moisture and with such a big temperature difference between the sea and air it has provided a lot of uplift and convection.

"The air is very unstable as it is so cold, meaning the warmer moist air rising up from the sea can take the moisture a lot higher into the atmosphere and develop large clouds, in this case cumulonimbus clouds. We've seen cloud tops reach 20,000ft on Sunday, where the air is currently around -45C (-49F).

"The cumulonimbus clouds can develop a charge difference between the top and the bottom if there is a strong updraft, which also helps to make the cloud larger.

"This charge difference then creates a bolt of lightning and the thunder is created from the air expanding quickly due to the extreme heat from the lightning bolt."

One of the reason for reports of thundersnow being rare is that the falling snow muffles the sound of the thunder, meaning that it is only heard across a smaller area than regular thunder.

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