People in and around Edinburgh were woken by the sound of thundersnow last week.
What is thundersnow?
Thundersnow is the name given to a wintry thunderstorm, that's associated with heavy snowfall rates, as well as thunder and lightning.
The 4 ingredients needed for thundersnow are moisture, lift, an unstable atmospheric temperature profile and below-freezing air in the cloud and near ground level.
Find out more in David M. Schultz and R. James Vavrek's paper 'An overview of thundersnow': https://rmets.onlinelibrary.wiley.com/doi/pdf/10.1002/wea.376