Why the rime frost has stuck around in Sask.

Why did we see such persistent fog and frost in Saskatchewan?

A stagnant air mass meant day after day of foggy, frosty weather

Saskatchewan has played host to some unusual weather over the past week. A temperature inversion at the surface, where cold air lies below warmer air, led to low-level cloud and fog which drove down visibility across the southern half of the province. 

With air temperatures well below the freezing mark, the water droplets in the air froze to trees and other vegetation, leaving gorgeous rime frost coating Saskatchewan's landscape.

Now, a few days later, the picturesque frost is still clinging on.

Why has the rime frost stuck around?

Over the last few days we have seen a stagnant, moisture-rich air mass over the prairies. Combined with that temperature inversion, it led to the persistent fog. 

With very light winds both at ground level and at high levels in the atmosphere and little sunshine over the weekend, Saskatchewan was trapped in a virtual weather snow globe. Not much change meant day after day of beautiful, frosty trees. 

The rime frost really built up thanks to the extended time in the freezing fog. Some trees even lost branches under the weight. 

The heavy frost has weighed down trees, causes branches to break in Regina. (Kirk Fraser/CBC)

How long will the frost last?

We finally have some movement in our atmosphere, meaning that the low level moisture will be flushed out of the province with winds out of the west. Though the south saw a little sun Monday, more snow is on the way with cooler temperatures Tuesday and Wednesday so we likely won't see much of that frost melting away.

What we will see into Tuesday and Wednesday is stronger winds moving in. Those gusty winds will blow some of the rime frost off the trees this week.


Christy Climenhaga (Saskatchewan)

CBC Saskatchewan Meteorologist

Christy Climenhaga, CBC Saskatchewan's Meteorologist, covers weather for the province. Catch her forecast tonight at 6 on CBC Saskatchewan News.


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