Wednesday, January 23, 2019

What actually is freezing rain?

English friends and family tend to react with incomprehension and horror when we talk about things like freezing rain and freezing drizzle, such as we experienced this morning. They are familiar with sleet and snow, and way too familiar with rain, drizzle, "mizzle" and fog. But freezing rain is not something Britain ever has to deal with, it seems.
And I think a lot of Canadians don't really understand what freezing rain really is, although they are quite familiar with its effects. So, what is freezing rain, and how does it work?
Freezing rain may start, at cloud level, as rain, snow or hail. But at some point it travels through a warmer layer of atmosphere where it melts to rain. It then falls through a relatively narrow band of much colder atmosphere, where it "supercools" to just above the freezing point. So, it continues to fall as rain (not as ice, snow or even sleet), but it is very cold. When it reaches the (very cold) ground, it spreads out and freezes on contact, covering the ground, cars, trees and power lines with a smooth coating of pure ice called "glaze ice". This can make driving and even walking treacherous and, in the case of a full-blown ice storm, can build up and weigh down trees and power lines until they snap.
So, make you feel any better? Thought not?

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