Glacial lake outburst flood

Glacial Lake outburst flood

Formation of Glacial Lake

Glacier lakes are formed in two ways. They are mentioned below.

1. Moraine dam lake

This type of dam lake is formed due to the movement of huge block of ice (i.e. Moraines). This type of Glacier lake are more dangerous and tend to burst.

2. Ice dam lake

This type of dam lake is formed by the impounding of the crystals of ice.

Causes of failure of Glacial lake

1. External factors

The external factors such as rock mass on collision with the dam causes failure and the continuous deposition of sediments into the lake may cause overflowing. This is how external factors cause failure of Glacier Lake.

2.  Increase in the volume

Due to the increase in temperature because of global warming, the moraines and ice tend to melt. This cause increase in the volume of water and increment in the water level and ultimately, causing overflow.

3. Activity of Glacial Lake

Rapid increment in the size may also lead to the outburst of the Glacier lake.

4. Position of lake

The surrounding and the nature of Glacier also determines the failure. In general, it has been found that the moraine dam lake have more failure than ice dam lake.

5. Condition of parent Glacier and Glaciers on the periphery

Sometimes, intermixing of Glaciers i.e. glaciers of different pressures causes the moraine or ice dam to weaken.

6. Condition of Moraine dam

The condition mentioned below affect the failure
a. Steep slope i.e. huge influence of gravity onto the Glacier lake.
b. Porosity of moraine dams also influences the failure.
c. Presence of Calcareous material in the dam that dissolves in water creating voids.
d. Newly formed moraines are not compact and hence, are determining factor.

7. Physical condition of surrounding

The following physical conditions cause failure of Glacial Lake.
a. Steep slope and possibility of rock fall in the area.
b. Collision of block carried by Moraines with the Glacier wall.
c. Earthquake is also a responsible factor.

Mitigation measures for Glacial lake outburst flood

a. By reducing the volume of water in the Glacial Lake by establishing out ways such as canals, siphon, pipes etc.
b. By maintaining a moraine dam and landslides at valley walls.
c. By establishing a monitoring system.
d. By establishing an early alarming system.
e. By developing awareness to the local people residing at the potential paths of Glacial lake outburst flood.