when you climb high grades the rock becomes extremely difficult to navigate and 'grip'. The common example is stacking 2-3 credit cards on top of each other and

when you climb high grades the rock becomes extremely difficult to navigate and 'grip'. The common example is stacking 2-3 credit cards on top of each other and looking at the edge from the top - thats the size of the rock people are holding onto and stepping on with all their weight. In some cases you won't even have a flat piece of rock to step on, imagine climbing a brick wall. Asides from the difficulty, there are obvious elements such as high winds when you're at that altitude, mist, rain, wildlife, etc.