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Heavy hoar frost deposits during recent cold weather

Posted: Mon Dec 05, 2016 10:10 pm
by Edward Graham
As it is still early in the winter season (and the air is still relatively humid and the seas are warm), we have had some heavy hoar frost deposits up here in Northern Scotland over recent weeks (thanks to abundant clear skies and light winds). At this time of year, it is a struggle for the Sun to reach upon any patch of ground that is not orientated southwards - and so hoar frost deposits have continued to build up during the daytime and right through into the following nights on a few occasions.
Here's a photograph that I took at Lews Castle College Stornoway on the evening of 21st Nov last (after 3-4 days of continuous hoar frost):
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It looks just like snow: indeed, one could almost make a snowball with the deposits.

And today (Mon 5 Dec), there's been another very sharp frost (-10C to -11C in some glens), and I see that the NASA Terra satellite snow algorithm is picking up the heavy frost deposits as potential snow (cyan colours in image) across the narrow glens of N Highlands - people in Inverness have told me on social media today that the ground is completely white there due to the subzero conditions with freezing fog all day and night:
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Eddie Graham, Stornoway, 5 Dec 2016

Re: Heavy hoar frost deposits during recent cold weather

Posted: Tue Dec 06, 2016 10:37 am
by John Wilson
We have had some heavy hoar frosts here on the edge of Sherwood Forest, but not as spectacular as yours, Eddie! Yesterday (Monday 5th) the hoar frost melted very suddenly starting at about 10.00 and had almost gone by 10.15. This saved me the trouble of scraping the car windows.
Regards to all
John