Anyone who has climbed ice knows how fragile and changing the medium can be. For more insight into the science of ice formation, I recommend this article on how ice climbs form, deform, change, and fall right apart.
An excerpt from the author, Will McCarthy:
Ice is weird stuff, though climbing it might just be weirder. Ice-climbing is also potentially painful: half the equipment has sharp metal points (like tools, crampons, and ice-screws) that mix well with neither the other half of the equipment (like clothes, pack, and rope), nor with the soft flesh of a climber. And then there’s the objective danger. Ice-climbs are temporary features of winter, and are in a perpetual state of falling down during their short life-spans. That’s the part of ice-climbing that’s potentially lethal. The paradox of ice-climbs is that they can provide the easiest and safest means of ascent of a cliff, or a mountain. The trick is to determine when an ice-climb is safe, and to do that requires knowing all about ice.