冻掉手指鼻子耳朵原来是真的有可能的

以前听说北方人冬天吃饺子，耳朵就不会冻掉下来，以为是很夸张的说法，今天才知道原来是真有根据的。 

据医学研究，当人体皮肤直接暴露在零度以下的低温中时，血管会剧烈收缩，正常血液循环就被打断，整片皮肤会变成紫红色。如果持续时间过久，肌体细胞中的水分就会结成冰晶，从而造成大量细胞失水死亡，这片皮肤又会变成苍白色，而且感觉又麻又痛，摸上去冰凉。如果连深层的肌肉甚至骨骼都被冻伤，那皮肤就会逐渐变黑、变干，到这个程度基本上就是很难恢复了，甚至需要截肢防止感染。 -- 知乎

Your body will sacrifice fingers and toes to survive in very cold weather. 
To stay alive in freezing temperatures, your body will automatically stop blood flowing to your fingers, toes, ears and other extremitie. This may eventually make these parts drop off, but it preserve heat from the rest of our body.    --<<what you should know about your body>>

Ice crystals form in tissue, causing skin to blister and turn black, Cells can die and body parts may drop off or need removing to prevent infection.