Ice spikes: A rare winter phenomena

Ice spike in plant pot
Ice spike in plant pot Credit: Paula Alcott, Andover

Cold weather may not be everyone's cup of tea but it does bring bout some weird and wonderful phenoma. One of the lesser-spotted icy features is the 'ice spike'.

Ice spike in bird bath Credit: Malcolm Spencer, Blue Bell Hill

But what causes these strange frozen protrusions?

When ice freezes in a container such as a plant pot, or a bird bath, it freezes from the outside in. As the ice layer thickens and spreads inwards, the water underneath is forced up through any weaknesses. This acts like a very slow-moving fountain and the water freezes as it's pushed upwards into the cold air.

Ice spike in garden container Credit: Carole Giles, Horndean

Ice spikes come in all sorts of different shapes and sizes and require very specific conditions - a light breeze is useful and nothing too cold otherwise the water will freeze to quickly. So next time you're braving the chill, keep your eyes open for an ice spike, it may be closer than you think!

Ice spike on hot tub Credit: Kelvin Reynolds, Oxford