According to WXCharts weather maps, unusual weather conditions are likely in areas around Fort William, Portree and Inverness, where 15mm/hour of freezing rain is possible.

THE Met Office states that freezing rain is a rare type of liquid precipitation that hits a cold surface and freezes almost instantly.

This can produce striking effects, as the raindrop momentarily spreads across the surface before freezing, enclosing the surface in a transparent layer of ice.

The forecaster explains: “Freezing rain is more common in other parts of the world, for example the United States, where weather systems produce a lot of freezing rain.

According to the latest maps, this rare weather event will bring more chaos to the north of the country. WXCharts maps show that while some areas in the north of the country will experience freezing rain on December 21, others will be covered in layers of snow of up to 11 cm.

Explaining how water droplets freeze, the forecaster explained: “Freezing rain tends to start its life as snow, ice, sleet or hail, but passes through a layer of air above 0°C descending towards the ground, merging into a droplet of liquid water.

“If these droplets then fall through an area of ​​frigid air just above the ground, they become supercooled.

“When these supercooled droplets hit surfaces near or below freezing, they freeze on impact, forming a layer of ice.”

The weight of the ice can sometimes be heavy enough to topple trees and power lines, and ground ice effectively turns roads and trails into an ice rink. Freezing rain can also be extremely dangerous for aircraft.

In its long-term forecast between December 21 and January 4, the Met Office says nothing about freezing rain but suggests a possibility of sleet and slow weather.

He said: “Mainly unsettled conditions appear likely for most, with spells of wind and rain followed by showers affecting most areas, but particularly towards the north or northwest.

“Some sleet and snow are also possible from time to time, particularly over the northern high ground. However, there are also signs that more stable conditions are possible at times, perhaps more likely in the south to the end of December or the beginning of January.

“Temperatures are expected to be around average overall, with more stable interludes bringing a risk of frost and fog.”