Scotland and other parts of the UK have seen the first significant snowfall of the winter as a cold weather alert was issued for the days ahead.
Some Scottish residents got an unusual wake-up call overnight and alerted police to explosions but what they were actually hearing was a natural phenomenon known as “thundersnow”.
This is the rare combination of thunderstorms formed in wintry conditions that bring heavy downpours of snow along with the usual thunder and lightning.
People woke up to bright snowy scenes having heard sounds which would have been quieter than usual thunder and lightning strikes.
Police Scotland Control Rooms said they had received a number of calls from people who were concerned after they heard explosions and strange noises.
They tweeted on Friday at about 5am: “Please do not be alarmed, we are currently experiencing thunder and lightning.”
The snow caused disruption across many areas, including temporarily shutting the Queensferry Crossing.
Traffic Scotland operator manager Douglas Cairns said the first severe weather warning of the winter for snow and ice had led to “some very challenging driving conditions”.
It was the coldest night of autumn/winter so far, with -9.6C (14.72F) recorded at Altnaharra, Sutherland, in the Highlands, as rain, sleet and snow fell across a broad swathe of Scotland and northern England, according to the Met Office.
The coldest night of the year is still -10.2C (13.64F) recorded at Braemar in Aberdeenshire on February 13.
A dusting of snow also lay over Kent and spread northward over the wealds and downs of south-east England.
With a risk of severe cold weather, icy conditions and heavy snow across parts of the country, Public Health England (PHE) is encouraging people to stay warm and look out for those most at-risk.
The Met Office has said there is a high chance that the north east of England, north west of England and Yorkshire and the Humber regions will be gripped by cold weather through to “at least” Tuesday evening.
Met Office meteorologist Bonnie Diamond said: “December has got off to a much colder start than last month, with widespread low temperatures bringing the risk of frost, ice and wintry weather across the country.
“With temperatures generally limited to between 4 to 7C by day and falling widely below freezing overnight, a cold weather alert has been issued covering much of northern England and will remain in place until at least next Tuesday.”
Dr Owen Landeg, of PHE, said: “Cold weather isn’t just uncomfortable, it can be bad for your health.”
PHE are telling people to keep warm and heat their homes to at least 18C, particularly if someone in the household has reduced mobility, is 65 and over or has a health condition, such as heart or lung disease.
Dr Landeg said: “Looking out for others at this time is also really important. Remember to check on frail or older neighbours or relatives, especially those living alone or who have serious illnesses, remembering Covid-19 social distancing, to make sure they are safe, warm and well.”
A number of yellow weather warnings for snow, rain and ice are in place.
A snow warning covering parts of central and northern England valid until Friday at 9pm warns of a looming mixture of rain, sleet and snow which may create tricky driving conditions.
Parts of eastern Scotland could be hit by some persistent heavy rain, with 20-40 mm of rain falling quite widely, according to a warning which runs until Saturday at 6am.
Freezing temperatures could take hold overnight in south-east England where a warning for ice has been issued from Friday evening through to Saturday morning.
Residents in Kent, the far east of Essex, Suffolk and Norfolk may face a few showers which could lead to more widespread ice in these areas, the Met Office said.