When thunderstorms form in wintry conditions they can sometimes give rise to heavy downpours of snow which are often called 'thundersnow'.
Thundersnow is unusual only because it can only occur in a few months of the year.
What does thundersnow look like?
When thundersnow occurs at night the lightning appears brighter - this is because the light reflects off the snowflakes.
Interestingly, the snow contained within the thunderstorm acts to dampen the sound of the thunder. While the thunder from a typical thunderstorm might be heard many miles away, the thunder during a thundersnow event will only be heard if you are within 2 to 3 miles of the lightning.