Glacial Landscapes – Glacier Advance, Retreat and Landforms
GeographyEarth's Structure & LandformsAges 15–16
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Sign in to playA map and long profile of a 30 km mountain valley. Change temperature and snowfall to shift the glacier's mass balance (accumulation, ablation and the equilibrium line) and watch the ice advance onto the lowland or shrink back to its corrie. Freeze–thaw, plucking and abrasion carve corries, arêtes, pyramidal peaks, a U-shaped trough, hanging valleys and a ribbon lake; retreating ice leaves terminal, recessional and lateral moraines, drumlins, erratics and an outwash plain. Panels add periglacial features and land use and tourism management in a glaciated upland.
Lesson: Glacial processes and landforms: mass balance, erosion, transport and deposition; periglacial landscapes; land use and tourism in glaciated uplands
What it shows
A glacier grows where more snow falls each year than melts. Above the equilibrium line altitude (ELA) accumulation wins; below it ablation wins, and ice flows downhill from one zone to the other. If the whole glacier gains mass it advances, if it loses mass it retreats, but it responds slowly. Moving ice erodes by plucking and abrasion while freeze–thaw shatters exposed rock, turning a V-shaped river valley into a U-shaped trough with corries, arêtes and hanging valleys. Debris dumped at the snout builds moraines, and lowland ice moulds drumlins and leaves erratics.
How to use
Drag Temperature ΔT and Snowfall, then watch the map, long profile and charts while the model runs; +1000 years jumps ahead. Press Glacial cycle to cool the climate to −6.5 °C and warm it again with two pauses. Click the map or profile to move the cross-section. Starting landscape switches between an untouched river valley and one shaped by a past ice age. Below, set Visitors per year and Tourism management to compare impacts.
Parameters you can change
- Temperature change from today -8–4 °C
- Snowfall compared with today 50–200 %
- Starting landscape V-shaped river valley, never glaciated, After a past ice age
- Tourist visits per year 0–10 million
- Tourism management No management, Footpath repair and stone pitching, Shuttle buses and limited parking, Honeypot sites and zoning
Questions to explore
- Why does the glacier keep advancing for a while after the temperature has stopped falling?
- How do a ribbon lake and hanging valleys form in the same glacial trough?
- What do a terminal moraine and erratics tell us about a glacier that has disappeared?
