Booming Ice

I drove down the hill from the village heading for the shops as the sun went down. At the bottom of the hill the lake was completely frozen so I stopped to take a look (and maybe a blip). The "look" turned into a "listen" because the ice was booming. It had frozen when the lake level was high and as the water level drops the ice occasionally cracks and booms as it absorbs the stresses. Sometimes the booms echoed around under the ice, sounding for a few seconds before fading away.
The keen ice-skaters are already in action. They consider falling through the ice an acceptable hazard and go out in groups equipped with throwing lines and spare clothes in a waterproof bag. I'll be waiting a while longer before I venture out as I prefer to know I'll stay dry!