by Susie Curtin.

I KNEW the morning was special the moment I woke up to the ethereal white light that seeped through my curtains. While we were all sleeping, the ice maiden was hard at work in the Vale. Quickly donning my boots and walm clothes, I have set out to explore the ‘snowy’ landscape that has transformed the ‘usual’ into the ‘unusual’.

As I walk over the fields and towards the River Stour, swirling disorientating pockets of mist and fog come and go adding to the sense of ‘strangeness’ and adventure. The cold air caresses my face and makes me feel completely awake and alive, despite the numbness of my hands. At first glance, I think the land is blanketed by a hoar frost but then I notice the alabaster shards, as fine as needles, that protrude from every blade of grass, bush and tree. This is the unique and exquisite structure of a rime frost. If, like me, you thought that frosts formed in the same way, then you might be pleasantly surprised to know how different freezing weather conditions determine the type of frost that occurs.

A ‘ground frost’ forms on still, cold and clear winter nights when water vapour condenses and then freezes on solid surfaces. A ‘hoar frost’, however, occurs much less frequently when water vapour in the night air touches solid surfaces whose temperature is already below freezing. In this instance, water molecules transform from a gas directly to a solid. Ice crystals form straight away and continue to grow as more water vapour falls and freezes. The result is a soft, pretty, feathery coating of ice on trees and vegetation. The word ‘hoar’ is derived from old English and refers to how the ice resembles ageing white hair or beard.
A rime frost, on the other hand, is borne from completely different circumstances. It is caused by tiny, supercooled water droplets in freezing fog that land on sub-zero surfaces and freezes immediately. In this case, water is transformed directly from liquid to solid. These rime deposits become long plumes of ice that often point in the direction of the light wind that has helped to form them. They are sometimes called ‘frost feathers’ and remind me of the slightly frightening pictures of Jack Frost in the fairytales of my childhood.

Walking through the woods and down beside the river, I find it impossible not to stop and take photographs of these strange ice forms as they adorn seed heads and the remains of yesteryear’s bullrushes. But already the sun is shining and the warmth of the sun’s rays are melting away nature’s artwork. All is quiet and still apart from the sound of droplets falling from the trees, like rain, and returning the moisture to the ground in the continuous movement of water within our Earth and atmosphere.
In the distance, I can hear the great spotted woodpeckers that live along this stretch coming alive in the rising warmth of the sun, as they drum the trees to denote their territories. It is lovely to have a reminder that spring is not far away despite the bitter cold of the night before. As I turn for home, the single whistle of a kingfisher announces his presence just in time for me to admire the dash of blue as he streaks downstream. How, I wonder, do these tiny creatures survive these bitter winter nights? But then, nature never ceases to inspire and amaze me.

Dr Susie Curtin (email curtin.susanna@gmail.com)