Glacial explosions, which occur when natural ice and sediment dams collapse, sending floods downstream, have emerged as an issue in Europe, Central Asia, and South America.
According to a report in Global, glacial explosion floods have claimed over 12,000 lives worldwide. The majority of these fatalities were concentrated in two events: the Huaraz flood in Peru in 1941 and the 2013 Kedarnath flood in India.
A 2023 survey published in Nature Communications revealed that approximately 90 million people across 30 countries reside in areas with glacial lakes, with around 15 million potentially affected by glacial explosions, particularly in India, China, and Pakistan.
Research conducted in 2023 identified over 120 glacial lakes in Alaska, with 106 having drained since 1985, many situated in remote locations, according to recent findings.
To address this year’s risks, Juneau has installed extensive barriers along the river to prevent widespread flooding in vulnerable areas. The funding for these barriers was partially sourced from Juneau residents living in flood-prone zones.
“We are still evaluating the barriers, but we believe they have significantly reduced property damage compared to the 2024 incident,” stated Nahak McFadden, spokesperson for the U.S. Army Corps of Engineers.
How Do Glacial Explosions Occur?
Glaciers, often referred to as slow-moving rivers of ice, descend the mountains’ slopes. During colder seasons, these ice masses accumulate as snow compresses into ice. In the summer, meltwater either escapes or the glaciers destabilize, leading to ice loss.
Initially, water flowing from the glacier enters rivers and eventually reaches the ocean.
Sometimes, the flow of meltwater is obstructed by glacial ice plugs, causing water to pool and form tunnels beneath the glacier, destabilizing these ice plugs.
“If sufficient water builds behind an ice plug, it can float the ice and move beneath it. The warm water initiates a cycle of positive feedback, thermally eroding the ice,” a researcher noted.
“Once triggered, they can unleash catastrophic flooding that surpasses even the most significant floods caused by rainfall or thaw,” he added.
Glacial explosions typically occur in Alaska during August when the meltwater reaches its peak, though they can happen at any time.
After drainage, glaciers may slowly move downhill, causing ice to crumble and restart the buildup cycle. Capps indicated a pattern where one explosion occurs annually.
Alaska is home to numerous lakes surrounded by glaciers capable of causing explosive floods. However, most of these locations are remote, minimizing risks to communities and infrastructure.
“In such a critical area like Suicide Basin upstream of Juneau, challenges arise primarily due to the infrastructure located downstream,” he pointed out.
Explosions can also occur if water overflows natural dams, known as moraines, composed of rocks and debris.
“Most often, but not exclusively, failures occur in moraine-formed lakes, leading to sediment being washed away,” Capps explained.
What Role Does Climate Change Play?
Globally, glaciers are retreating. While some glaciers may grow during seasons of heavy snowfall and cooler temperatures, many diminish under the sun or during periods of low snowfall. Overall, there’s a longstanding decline in global glacial mass.
The World Glacier Monitoring Service tracks data from 60 “reference” glaciers, each with mass balance assessments spanning over 30 years.
“The declines are significant and consistent globally,” mentioned Pelt, who monitors glacial mass changes in Washington’s North Cascade range. “2023 marked the first year where all 60 glaciers recorded a loss in mass balance concurrently, a trend that continued into 2024.”
Research indicates that glaciers have been thinning since 1985, as they retain less water behind progressively shorter and thinner ice barriers. The occurrence of these explosive events has remained relatively stable over time.
As glaciers recede, some flood-prone areas may cease to function.
“I believe the danger will lessen for residents in Alaska,” Pelt stated. “The glaciers are thinning and retracting, reducing the likelihood of robust ice dams forming.”
However, researchers are wary that glacial dams at higher altitudes and in colder regions might become unstable as global temperatures rise, potentially leading to newly formed lakes and explosion-prone areas.
In Juneau, the barriers successfully held after implementation following last year’s disaster. The Startz family had a minor pond in their yard along with a thin layer of glacial silt on their grass.
Homeowners in flood-risk zones contribute over $600 annually for protective measures.
“If these barriers prove effective, then I’m more than willing to pay that extra fee,” remarked Stars on Tuesday. “We can’t repair a glacier.”
Source: www.nbcnews.com
