Never seen that, but mine have been walking very slowly over the snow. They don't like it at all, nor do I for that matter. Do you get them inside at night so they are cosy? I have two that won't go in the pop hole so every night for the last three weeks I have been going into their run and putting them through in the vain hope they will suddenly click it is the best place to be on a night like this. Hope your girl is OK in the morning.