Iran has experienced its heaviest snow in 50 years, while British soldiers serving in Afghanistan have seen their first proper flurries of the white stuff in Camp Bastion.
About 500,000 people are trapped in their villages in northern Iran, many without electricity or gas, after snow began falling on Friday.
The white storm is "unprecedented for the past 50 years, with two metres (almost seven feet) of snow falling since Friday", a Mazandaran provincial official said.
"Our main problems are (the provision of) power and water, which have been cut off due to the heavy snow."
About 11,000 people have had to be rescued during the past four days, with some being rehoused in emergency shelters, while at least seven Iranians have been taken to hospital.
In Tehran, temperatures plunged to -7C (19F) on Saturday, making it the capital's coldest night of the year, while other provinces experienced temperatures as low as -18C.
The snow is expected to blow into the southwest of the country from Monday night.
In Afghanistan, soldiers have seen their first covering of snow at Camp Bastion since the main British base in Helmand Province was established in 2006.
Last week, they were enjoying temperatures of 21C (70F). In summer, they can soar to a sweltering 50C (122F).
A rare weather pattern has been blamed for the rapid change in conditions.
Service personnel took the opportunity to build a snowman, while Apache helicopters were coated in white.
"It was amazing to see. This is a place where the sun beats down for much of the year and it reaches more than 50C in the summer months," said Captain Rory O'Shea, from Twyfor, Berkshire, who works in Task Force Helmand's headquarters, now based at Camp Bastion.
He said although it gets cold and rains, there has been no snow to speak of up to now.
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