English: Hypothetical scenario showing the interaction between two floes of very different thicknesses, with the thinner one (right) failing against the other (left). The result is a pressure ridge, a linear pile-up of ice blocks that runs along the contact between the two floes. Inside the thicker floe, in this case a slab of old ice (sea ice that has survived at least one summer), are the remnants of a pressure ridge which has been weathered down to a mere undulation. The bear provides an approximate scale in this example.