Insights & News

Frost – Part 2: Darker Side

10th December 2019

Part one explored the bright side of frost, in its many wondrous forms.
Now, we come to the more applied effects of frost.


Frost and Fragility

First, I’ll quickly cover plants! The vulnerability of tender spring growth to frost is widely known. Winter frosts aren’t usually considered such a problem, with only hardy evergreen plants under attack, but believe it or not, hard or prolonged frosts can cause them damage.

In fact, their leaves may become ‘scorched’ and if enough are damaged this way, the plant can die.

Concerns for Construction and Commuters

Some components of our infrastructure are vulnerable to severe damage from frost.

For example, fresh concrete below 5Nmm-2 strength can be cracked internally by water in the mix freezing. This is because ice is less dense than water, which means freezing results in expansion (by 8-10%). The concrete must be protected during its initial strengthening phase – which can be an extra few weeks long, compared to usual, in low temperatures: Lengthening the time it is at risk of internal damage while setting.

Expanding ice is also responsible for a type of damage that has caused untold stress to countless commuters. Yes, I’m talking about road cracking and potholing. Millions of euros are spent each winter repairing such damage in Europe. The work brings delays and diversions.

An example of damaged paving. As a keen road-cyclist, just looking at this makes me shudder!

Most of this work occurs in countries lacking in frost-resistant pavement (FRP) application. These are ones where frost is highly variable from winter to winter, making it hard to justify the expense and workload required to sufficiently research frost patterns for effective use of FRP.

So yes, frost has a sneaky side behind its sparkle.

What About Frost’s More Dramatic Cousin?

Well, as seriously disruptive as snow can be, it’s not as likely to cause structural damage. You see, that’s mostly the result of water freezing, which has already happened in snowflakes. In fact, air bubbles within a snow layer make it a poor conductor of heat – so it insulates the ground!

That means that if it turns sub-zero above the snow, the ground may be kept above freezing.

Speaking of snow, my next, festively themed blog piece will check out where you’re most likely to find it lying during the festive week 😉.


James Peacock MSc

Head Meteorologist at MetSwift

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