ngozumpa

Can you believe that THIS is what a glacier looks like? True story - it’s called a supraglacial lake, and it literally sits atop the glacier. There are several types of supraglacial lakes, classified largely by their location within the glacier. “Base-level” lakes are at the hydrological base of the glacier, while “perched” lakes are literally HIGHER than base-level lakes. It is theorized that perched lakes drain into base-level lakes through ice tunnels that run through the glacier.

The biggest supraglacial lake on the Ngozumpa glacier is Spillway Lake, and it is classified as a “moraine-dammed” base-level lake. This means that it rests behind the terminal moraine - the buildup of debris and ice at the glacier’s snout. These types of lakes can be dangerous, because, if the natural debris dam breaks, a massive flood could ensue. These events are called Glacial Lake Outburst Floods, or GLOFs, and have been recorded in Nepal and Bhutan for decades. It’s difficult to predict when a GLOF might occur, and this makes moraine-dammed lakes particularly fearsome.