Worried locals in the Scottish capital Edinburgh were woken overnight on Thursday evening by what some thought was a series of explosions.
Except, the city wasn't being hit by blasts. Instead, it was at the centre of a rare weather phenomenon: so-called "thundersnow".
That is when thunder and lightning occur at the same time as snowfall.
Police said they received a number of calls from residents in the area who thought they were hearing an explosion.
What is 'thundersnow' like?
According to the UK Met office, thundersnow can only occur during a few months of the year when the weather conditions are right.
The storm can produce spectacular sights; the forks of lightning appear brighter as they reflect off the falling snowflakes.
The snow also muffles the sound of the thunder meaning you can only hear it if you're within two or three miles (three or five kilometres) of the lightning - in a normal rainstorm, you can hear the thunder from much further away.
Parts of the UK get first snow warnings of the winter
Upland areas of South Lanarkshire in Scotland saw as much as 13 cm of snowfall on Thursday night with temperatures falling below -9℃ in places.
The cold snap is set to continue into this weekend, meaning road conditions can be more dangerous, warned Traffic Scotland.
“The first severe weather warning of the winter for snow and ice led to some very challenging driving conditions [on Friday]," warned Traffic Scotland operator manager Douglas Cairns. "It’s yet another timely reminder for people to check they are winter-ready and to make appropriate preparations or consider if they even need to travel when the weather is so severe.
Wintry conditions are also sweeping across much of Europe. Earlier in the week, Russia experienced a fresh pelting of snow.
Ordinarily, Europeans would be preparing for a busy ski season as the white stuff begins to blanket the Alpine peaks.