I've noticed that some freeze dried puddles, have a series of circles on them, like a weather map and wondered what could cause them.

During a prolonged cold spell during this year's winter in the UK, I noticed some unusual ice crystals which appeared to be "growing" out of a stone in the garden (attached picture).  The temperature had been below 0 degrees for about 10 days but most of the frost had gone from the other stones around this particular one. 

The height of the ice crystals was around 1 cm with the overal size of the stone around 5 cm although the ice covering was very patchy.  Could a porous stone create this effect when the water inside freezes and is forced out of the pores...?

I have noticed that my car is easier to defrost on mornings when my car is cleaner than when it hasn't been washed for a few weeks.

Is this because I only wash my car on days with nice weather which means that it isn't quite as cold the following morning? Or could there be an explaination around ice sticking to the grease/dust etc?

While walking in the hills above Coniston, Cumbria, I came across a lake that was covered in ice formed of loosely joined columns about 5mm in diameter and 50mm long. Does anyone know how they may have formed?

The photos are from our bird bath in the back garden in Bedford this week. There was a hard frost overnight and the water in the bath froze over. This protuding piece of ice was there in the morning. There is nothing overhanging the bird bath in the vicinity and the nearest tree is a long way away. It looks as if something disturbed the water but it surely was not cold enough (around -4 to -6C) for this amount of water to freeze instantly I would have thought. 

This water was in a plastic sheet covering up a canoe, the water is around 10cm deep. What caused these crystals to form in this manner?

I saw the delicate, leaf-like ice crystals in the photo whilst snowboarding in France, they measured from 20 - 80mm and were incredibly fragile. The area they covered in the photo was about 20m2 but we saw other patches close by. The site was at about 1800m.

I refilled my ice cube tray, put it in the freezer.  When I came back a couple hours later, I noticed a slender vertical spike protruding from the center of the ice cube.  What would cause the water to freeze in this manner?

I was walking along a canal several days ago, and, the UK weather being what it is at the moment, the canal was frozen. However under all the bridges that crossed the canal, whether footbridge or road bridge, the water was unfrozen. What is it about the bridges that stops the water under them from freezing?