Learning from a disaster event: Investigating the 2018 Panjshir flood in Afghanistan

In a case illustrative of effective inter-agency collaboration and resource sharing, the flash flood in Panjshir Valley, north-central Afghanistan, on 12 July 2018 – which led to 10 people losing their lives – was investigated using satellite imagery and backed by on-site field appraisal. This joint post-disaster investigation identified the cause of the flood – a glacial lake outburst – and stressed the need to establish a mechanism for regular monitoring of glacial lakes. It also pointed to the importance of setting up early warning systems and creating awareness among downstream communities. The national authorities involved thereafter swiftly commissioned a feasibility study for the installation of flood early warning systems in Panjshir.

A mosque in Peshghor Village, Afghanistan, is covered by debris brought by the flood.
(Photo: Waheedullah Yousafi/ICIMOD)

Experts working within the SERVIR Hindu Kush Himalaya (SERVIR-HKH) initiative at the International Centre for Integrated Mountain Development (ICIMOD) led the investigation following a special request from the Department of Water Resources (WRD), Ministry of Energy and Water (MEW) in Afghanistan. They tracked the course of the flood to a glacial lake upstream using a combination of freely available satellite imagery for the days leading up to and after the event. A joint field mission comprising WRD and ICIMOD staff also visited the glacial lake and conducted a field assessment.

Glacier debris after the flood Image credit: MEW

Field photographs showing cracks in the moraine dam at the lake snout and remnants of the lake after the breach. Image credit: MEW

The team deduced that a breach in the natural moraine next to the glacial lake triggered the flash flood, which they identified as a glacial lake outburst flood (GLOF) event. Analysis of hi-res Pleiades imagery with a ground resolution of 0.5 m in-house – procured gratis following a special request through the United Nations Platform for Space-based Information for Disaster Management and Emergency Response (UN-SPIDER) programme to Airbus Defence and Space – helped confirm the breach in the natural moraine. Field photographs from the joint mission further corroborated that a glacial lake outburst had caused the flood. 

Besides damaging buildings and agricultural land, the flood inundated a bridge, completely washed
out two bridges, and destroyed the intake site for an irrigation canal and about 400m of the canal.

Flood waters from the glacial lake situated at an altitude of 4500 masl travelled 14 km down the tributary to its confluence with the Panjshir River. Pre- and post-event satellite imagery also revealed several small landslides along the flooded river as a result of toe cutting by the flood along the narrow river stretch. Peshghor Village, located 12 km downstream of the glacial lake, suffered the most damage. The flood destroyed infrastructure, caused the closure of a major highway, and damaged fertile agricultural land, thereby adversely affecting the livelihood of the villagers.

The GLOF deposited debris along its path. At some points, the debris was more than 2.2 metres high. (Photo: Waheedullah Yousafi/ICIMOD)

Tons of debris swept out from the narrow river valley upstream and spread into the valley below. Consequently, the main Panjshir River was dammed and a temporary lake was formed in the river. The lake formation further inundated agricultural land, houses, and roads along the river up to 1.7 km from the confluence.

Upon completion of the investigation, ICIMOD submitted a technical report to the WRD and recommended identifying and monitoring potentially dangerous glacial lakes. ICIMOD suggested the installation of networks of real-time sensors to measure the rise and discharge of glacial lakes and early warning systems. These measures will provide sufficient lead times to avert GLOF-associated disasters and minimize damage.

The joint ICIMOD–WRD mission also conducted a second and thorough assessment of the flood-affected area. The WRD submitted findings from the field-based and remotely sensed investigation in an official communication to the president’s office in Kabul. Subsequently, the WRD, ICIMOD, and the Aga Khan Agency for Habitat (AKAH) have commissioned a detailed feasibility study for the installation of community-based flood early warning systems in the Peshghor and Pariyan areas of Panjshir. ICIMOD, under its Strengthening Water Resources Management in Afghanistan (SWaRMA) Initiative, will support the installation of such systems in Panjshir with technical assistance from AKAH.

The lake formation due to debris from the flood further inundated areas along the river up to 1.7 km from the confluence. (Photo: Waheedullah Yousafi/ICIMOD)

Under changing climate conditions, the formation of new glacial lakes is a common process in the high mountains of the Hindu Kush Himalaya. Concomitantly, the danger these lakes present to downstream communities and ecosystems is also ever present. Undertaking periodic assessments to identify potentially dangerous glacial lakes and monitoring such lakes can be vital in minimizing the damage from disasters like the Panjshir flood in the future. With recent advancements in technology and improvements in resolutions and availability of satellite data, Earth observation can help developing countries understand the nature and causes of disasters and adequately address them.

Findings from the ICIMOD investigation have been also been made available as a story map for the general public on ICIMOD’s website.

Written by Utsav Maden of SERVIR-HKH/ICIMOD. This article was originally featured on SERVIR-HKH's website. Click here to go to the original post.

Note:
SERVIR Hindu Kush Himalaya (SERVIR-HKH) is implemented by ICIMOD and prioritizes activities in Afghanistan, Bangladesh, Myanmar, Nepal, and Pakistan.