What is a Glacial lake

✅ A glacial lake is a body of water with origins from glacier activity. 

✅ They are formed when a glacier erodes the land, and then melts, filling the depression created by the glacier.

० Formation

✅ Near the end of the last glacial period, roughly 10,000 years ago, glaciers began to retreat.

✅ A retreating glacier often left behind large deposits of ice in hollows between drumlins or hills. 

✅ As the ice age ended, these melted to create lakes.

✅ These lakes are often surrounded by drumlins, along with other evidence of the glacier such as moraines, eskers and erosional features such as striations and chatter marks.

✅ The moraine creates topographic depression in which the melt water is generally accumulated leading to formation of glacial lake. 

✅ When this lake is watertight, melt waters will accumulate in the basin until seepage or overflow limits the lake level.

✅ Such moraine-dammed lakes appear to be the most common type of glacial lakes.

✅ The impoundment of the melt may sometimes be unstable, leading to sudden release of large quantities of stored water. 

✅ Failure of these ice or moraine dams leading to disastrous destruction events has been documented throughout the world. 

✅ Flash floods caused by the outburst of glacial lakes, called as Glacial Lake Outburst Flood (GLOF), are well known in Himalaya where such lakes had often been formed by landslides.

✅ The formation and characteristics of glacial lakes vary between location and can be classified into

◼️ glacial erosion lake,

◼️ ice-blocked lake, 

◼️moraine-dammed lake, 

◼️other glacial lake,

 ◼️supraglacial lake, and

 ◼️subglacial lake.