裂缝边缘 meaning in English

edge of crack

The white leader can now prepare the lip of the crevasse for hauling by placing an ice axe under the haul rope ( make sure to clip the axe into another anchor further back so it can ' t fall onto the victim ' s head if the lip breaks )
白队先锋这时候在拖曳绳（译者注：指黑绳）下面置入一支冰镐（确定将冰镐扣入较后位置的另一个确保点，这样如果裂缝边缘破裂的话，冰镐才不会砸到落难队员的头部）。
The white leader can now prepare the lip of the crevasse for hauling by placing an ice axe under the haul rope ( make sure to clip the axe into another anchor further back so it can [ chr ( 39 ) ] t fall onto the victim [ chr ( 39 ) ] s head if the lip breaks )
白队先锋这时候在拖曳绳（译者注：指黑绳）下面置入一支冰镐（确定将冰镐扣入较后位置的另一个确保点，这样如果裂缝边缘破裂的话，冰镐才不会砸到落难队员的头部）。