GLACIAL LAKE OUTBURST

 

Introduction 

Sudden release of water from a glacier lake is called Glacier Lake Outburst Flood (GLOF). This can threaten human lives and cause damage to the environment & infrastructure. The scientific community is currently focusing on monitoring of existing glacier lakes, identifying sites where glacier lakes are likely to form in the future, and measures to prevent floods or minimize damages.

A Glacial Lake Outburst Flood, or GLOF, is sudden release of water from a lake fed by glacier melt that has formed at the side, in front, within, beneath, or on the surface of a glacier.

A jökulhlaup is an occurrence similar to a GLOF, where a pool of water contained by a glacier melts or spills over the glacier. The dam can consist of glacier ice or a moraine in the terminal.

Characteristics

GLOFs have three features:

They involve sudden releases of water.

They tend to be rapid events, lasting hours to days.

They result in large downstream river discharges 

How does GLOFs occur?

GLOF can be impounded by moraine complexes, glacial ice or even bedrock and, as a result of breaching, slope failure, overtopping or other failure mechanisms, lead to catastrophic phenomena in the high mountains that threaten people’s lives, livelihoods and regional infrastructure.

 

HOW MORAINE DAMS LAKE FORMED?

A moraine is material left behind by a moving glacier. It includes soil, rock, ice, small boulders,

 etc. As glaciers move, they carry this debris which keeps accumulating in places. Over time, such

 moraines form natural dams. The moraine creates a topographic depression in which the melt

 water is generally accumulated leading to the formation of a 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. 

. If the lake is formed on the surface of the glacier, it is known as supraglacial lake. 

Causes of GLACIAL LAKE OUTBURST 

Failure may occur because of different causes, such as:

CLOUDBURST : A cloudburst is an extreme amount of rainfall in short period of time , sometimes it is accompanied by thunderstorm which creates flood.

 SNOW AVALANCHE: A rapid flow of snow down a hill or mountainside.

 LANDSLIDE: The movement of large mass of earth down a slope. 

MELTING OF MORAINE 

 VOLCANIC ERUPTION OR EARTHQUAKE BENEATH THE ICE OR UNDER THE ICE

 OUTFLOW: Displacement of water as a substantial part of an adjacent glacier collapses into a glacial lake.

In the Hindu Kush Himalaya, moraine-dammed glacial lakes are common and numerous GLOF events have been traced back to the failure of moraine dams. A moraine-dammed lake forms as a glacier retreats, and meltwater fills the space between the proglacial moraine (in front of the glacier) and the retreating glacier.

As the volume of the glacial lake grows, so does the pressure on the dam containing it. Fragmentation of the source glacier, landslides and other processes can trigger displacement waves in the lake, potentially compromising the stability of the dam and resulting in a GLOF. Failure of the dam can also occur due to internal processes, such as water seeping through the structure.

In 2018, ICIMOD released a report on the status of glacial lakes in the HKH that mapped and classified more than 25,000 glacial lakes in the five major river basins spread across the region. 8.3% of the glacial lakes are located below 4000 masl.

Impact of GLACIAL LAKE OUTBURST 

The effects of GLOF disasters (especially debris flows) are difficult to predict, and seriously affect the lives and properties of residents in the downstream communities, as well as the transportation, infrastructure, agriculture, tourism.

YOU TUBE : LETS LEARN GEOGRAPHY 

BLOG: GEOGRAPHIA // www.geographia97.blogspot.com

Facebook : www.facebook.com/@mygeo29/ 

Telegram : https://t.me/geographia29

Twitter :- LETS LEARN GEOGRAPHY

Sayantani Singh

READ MORE 

GEOGRAPHIA

If you want to join my telegram group 

Click here

FOR DOWNLOAD THE PDF 

1. FILE NAME: SOIL OF INDIA

2.FILE SIZE: 6.5mb

3. DOWNLOAD FILE: CLICK HERE 

GEOLOGICAL TIME SCALE IN ENGLISH CLICK HERE 

GEOLOGICAL TIME SCALE IN BENGALI  CLICK HERE .

পৃথিবীর অন্দরমহলের বর্ননা click here

interior structure of the earth click here 

KANT GASEOUS HYPOTHESIS CLICK HERE 

কান্টের গ্যাসীয় মতবাদ CLICK HERE

Free note for REMOTE SENSING AND GIS CLICK HERE

Regional planning in india click here

NCERT CLASS_6 SHORT NOTE CLICK HERE 

NCERT CLASS _6 SOLUTION CLICK HERE

ICSE class -ix click here

ICSE class -x click here

CLASS 6 WBBSE GEOGRAPHY CLICK HERE

জলবায়ুর শ্রেণীবিভাগপ্রশ্ন-উত্তর click here

REGIONAL THEORIES CLICK HERE

দ্বাদশ শ্রেণী ভূগোল CLICK HERE

CURRENT AFFAIRS CLICK HERE

NOTES OF HUMAN GEOGRAPHY AND AND POPULATION GEOGRAPHY click here

CONTINENTAL DRIFT THEORY BY FB TAYLOR CLICK HERE

CONTINENTAL DRIFT THEORY BY TAYLOR IN BENGALI CLICK HERE

CONTINENTAL DRIFT THEORY BY WEGNER CLICK HERE

CLIMATE OF INDIA CLICK HERE

ভূমিরূপ গঠন কারী প্রক্রিয়া ; উচ্চমাধ্যমিক ভূগোল click here

বহির্জাত প্রক্রিয়া ও তার ফলে সৃষ্ট ভূমিরূপ click here

মহিসঞ্চারন তত্ত্ব click here

Ugc net 2007 june paper 2 geography click here

Ugc net 2006 december paper 2 geography click here