Monday, 20 January 2014

Rain on a freezing day

A most unusual phenomenon. It is -7C this morning; it is damp (93% humidity) and windy (gusting to 40 kmh). As a result the perceivable temperature (temperatura odczuwalna or wind-chill factor - erroneously so, as it doesn't include the effect of humidity) feels like -12C.

I'm walking along ul. Poleczki; it feels very cold; my gloved hands are buried deep in the pockets of my M-65 parka. And yet - rain, not snow, is falling on my face. Which makes me think that it shouldn't feel like -12C, but rather +2C. Weird! This rain has been falling since yesterday morning, settling on the earlier snow and instantly turning to ice. Walking over grass covered with snow and then such an icy crust is unsettling - a 'slip-crunch' with every footstep as the foot goes through the ice.

Thanks to Martin Earle for pointing out via Twitter that this phenomenon is called (unsurprisingly) freezing rain - there's a very good Wikipedia article about it - particularly interesting is the way this occurs. Snow falling from a cold air mass passes through a warmer air layer, where it turns to rain, which does not have the chance to re-freeze as it enters a colder layer before finally hitting the ground in liquid form - and only then freezing.

The pavements would have been dreadfully slippery, but for the efforts of the urban roads department, which ensured that most of Warsaw's thoroughfares were treated with road salt, the pavements with sand too. So I walked a kilometre and half from Poleczki Business Park to ul. Puławska without any skids or slips (below).

Today of course was Blue Monday, a bit of pop-science that's struck a chord with the media and the general public as the most depressing day of the year, the Monday of the last full week in January. It is when Christmas has been long forgotten, and yet when spring is still a long way off. Leaden skies, howling winds, pervasive dampness and bitter cold have helped lower spirits, but my take is - we're over the worst. Spring may be two months away (or more - we had snow in Warsaw at Easter last year) but the days are getting longer. But there's more cold on the way - Thursday morning promises to be -18C (perceivable -24C).

This time last year:
Jeziorki in the snow (a much nicer day than today)

This time two years ago:
Winter's slight return

This time three years ago:

This time four years ago:
Pieniny in winter

This time five years ago:
Wetlands in a wet winter

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