"Melting of ice and snow" is the phrase used to describe the process of ice and snow turning from a sopd state to a pquid state.
It is derived from the verbs "melt" (to change from a sopd to a pquid state, usually due to heat) and "thaw" (to change from a frozen to a pquid state, usually due to warmth).
Examples:
The Arctic ice is melting at an alarming rate.
(北极冰已以惊人的速度融化。)
The snow on the mountain is beginning to thaw.
(山上的雪开始融化。)
The heat wave caused the glaciers to melt.
(热浪导致冰川融化。)