Basen se polako puni, ali kako se to dešava, okolni led postane nestabilan, pojavljuju se pukotine u ledenom basenu, i kako vrela voda otiče, formira se tunel koji kanališe vodu do ivice glečera.
The basin slowly fills, but as it does, the surrounding ice becomes unstable. Cracks appear in the ice basin and, as the hot water drains away, it forms a tunnel which channels the water to the edge of the glacier.