Understanding the Phenomenon of Surging Glaciers

Glaciers, those massive rivers of ice formed from compacted snow over centuries, typically creep along at a snail's pace, sometimes mere centimeters per day. However, a small but significant subset known as surging glaciers defies this norm. These dynamic ice masses periodically enter a phase of rapid acceleration, surging forward at speeds up to 100 times faster than usual, often advancing their fronts by kilometers in months. This behavior, termed a glacier surge, involves the sudden transfer of ice from higher elevations to the terminus, driven primarily by a temporary reduction in friction at the glacier's base. During the quiescent phase between surges, the glacier rebuilds mass through snowfall, setting the stage for the next explosive movement.

The process unfolds in distinct stages. First, thermal or hydrological changes at the bed—such as water lubricating the interface—reduce basal drag. This triggers unsteady flow, where the glacier 'saves' ice upstream before 'spending' it downstream in a dramatic advance. Cycles repeat every 5 to over 100 years, making prediction challenging even for experts. Step-by-step, a surge begins with subtle velocity increases, escalates to peak flow rates exceeding 100 meters per day, and culminates in front advancement, often accompanied by surface crevassing and medial moraines forming from recombined ice streams.

Global Inventory: Mapping 3,100 Surge-Type Glaciers

A groundbreaking global analysis has cataloged approximately 3,100 surge-type glaciers worldwide, representing about 1% of all glaciers yet covering nearly one-fifth of the planet's total glacier area. These are not evenly distributed; instead, they cluster in specific hotspots where climatic conditions favor surge development. The Arctic and sub-Arctic regions host 48.3% of them, including dense concentrations in Svalbard, where surging is a hallmark of the landscape. High Mountain Asia claims 50.5%, particularly the Karakoram and Pamir ranges straddling Pakistan, India, China, and surrounding nations. The Andes contribute a smaller share, with notable activity in Patagonia and the tropical Andes.

This uneven distribution ties to environmental factors: cold winters for thick snow accumulation, polythermal bed conditions allowing water buildup, and specific topography channeling instabilities. University researchers utilized satellite imagery from missions like Landsat and Sentinel, combined with historical records, to compile this inventory, revealing patterns invisible to ground observations alone.

University of Portsmouth Leads Landmark Research

At the forefront of this discovery is the University of Portsmouth's School of the Environment and Life Sciences, where Senior Lecturer Dr. Harold Lovell spearheaded an international collaboration. Joined by experts from Durham University, Simon Fraser University, University of Oslo, and others—including institutions in Iceland, India, Nepal, and Argentina—the team published their comprehensive review in Nature Reviews Earth & Environment.Access the full study here. Their work synthesizes decades of data, employing advanced remote sensing to track surge histories and project future behaviors.

"Surge-type glaciers are very unusual and can be troublesome," notes Dr. Lovell, likening them to a savings account spent wildly on Black Friday. Co-author Professor Gwenn Flowers from Simon Fraser University adds that climate change is "rewriting the rules," complicating hazard protection. This multi-university effort underscores the value of interdisciplinary glaciology research, training PhD students in satellite analysis and field hydrology while addressing real-world risks.

The Six Major Hazards Posed by Surging Glaciers

Surging glaciers unleash a cascade of dangers, far beyond steady melt. Researchers delineate six primary hazards:

• Glacier advance: Rapid front movement overruns roads, villages, and farms, burying infrastructure under tens of meters of ice.
• River blockages: Advancing tongues dam valleys, impounding unstable lakes that burst in glacial lake outburst floods (GLOFs), releasing billions of cubic meters of water.
• Subglacial meltwater outbursts (jökulhlaups): Pressurized water erupts from beneath, flooding downstream without warning.
• Sudden detachments: Steep surges calve massive ice-rock avalanches, devastating slopes.
• Widespread crevassing: Accelerated flow fractures surfaces, endangering travelers on glacial highways or climbers.
• Iceberg calving in fjords: Sudden releases generate tsunamis or shipping hazards.

At least 81 surges have historically caused such events, with potential for loss of life and billions in damage.

Photo by David Trinks on Unsplash

Case Study: Shisper Glacier's Repeated Outbursts in Karakoram

In Pakistan's Karakoram range, Shisper Glacier exemplifies surge perils. From 2017 to 2019, it advanced 3 kilometers, damming the Hassanabad River and forming a 3.5 km² lake. Multiple GLOFs between 2019 and 2022 eroded the Karakoram Highway—a vital Pakistan-China artery—disrupting trade and stranding communities. Damage exceeded millions, with sediments burying farmlands. Wadia Institute of Himalayan Geology researchers documented velocity spikes to 200 m/day, highlighting how surges amplify flood risks in densely populated valleys.

Similar events at nearby Aggi and Kyagar Glaciers underscore regional vulnerability, where 163 surge-type glaciers span over 6,000 km². Local universities like those in Dehradun monitor via ICIMOD networks, integrating community early warning systems.

Svalbard: Arctic Surge Hotspot and Research Frontier

Svalbard, Norway, boasts over 200 surging glaciers, like Nathorstbreen, captured mid-surge in 2012 by Dr. Lovell. These polythermal glaciers surge due to basal water buildup during cold quiescence, advancing fronts by 10+ km. Hazards include jökulhlaups flooding Adventdalen valleys and crevassed routes used by tourists and miners. University Centre in Svalbard (UNIS) leads fieldwork, training students in radar interferometry to forecast surges, vital as tourism grows amid thinning ice.

Climate Change: Rewriting Surge Dynamics

Contrary to intuition, surging heightens vulnerability to warming. During active phases, thin margins expose more bed to melt, accelerating loss. Extreme events—heavy rains or heatwaves—now trigger off-cycle surges by injecting water prematurely. In High Mountain Asia, frequency rises with melt lubrication; Iceland's may cease as glaciers shrink below critical mass. Projections suggest shifts: more surges in Canadian Arctic, potential emergence in Antarctic Peninsula. Portsmouth team's models integrate IPCC scenarios, urging emissions cuts to stabilize behaviors.University of Portsmouth press release

81 High-Risk Glaciers: Prioritizing Threats

Of the inventory, 81 stand out for proximity to populations and repeat surging—mostly Karakoram giants like Shisper. These threaten 10+ million downstream, endangering hydropower, highways, and agriculture. Durham and Oslo researchers prioritize them via hazard indices, factoring size, surge history, and exposure. Implications ripple globally: disrupted Silk Road trade, refugee risks from floods.

Photo by Roman Kraft on Unsplash

University Innovations in Monitoring and Mitigation

Academic centers drive solutions. Sentinel-1 radar detects cm-scale shifts; machine learning at Newcastle University automates inventories. Simon Fraser models basal hydrology for forecasts. Ground truths from ICIMOD drills subglacial lakes. Early warnings via SMS reach Karakoram villages, reducing fatalities 50% in tests. Glaciology programs at Portsmouth train next-gen experts in these tools, blending fieldwork with AI.

Future Outlook: Research Imperatives

As surges evolve, universities call for high-res satellites, basal probes during surges, and coupled ice-climate models. Collaborative networks like those behind this study position academia to safeguard billions. Reducing warming limits unpredictability, preserving water towers for 2 billion. Emerging careers in cryospheric hazards beckon students passionate about planetary resilience.

For deeper insights, explore glaciology at leading institutions via specialized programs and fellowships.