When you are on a glacier covered with snow, it may be difficult to visually detect crevasses. Just see the picture below. Who would say that there are crevasses on that glacier? But there are many of them under that smooth surface.
Is Glacier Meltwater Safe to Drink?
In this text you have my thoughts about drinking glacier meltwater, with some potential hazards mentioned, and with the ways of dealing with it if you have to drink glacier water. I myself never drink such a water before it is filtered.