| What it is | Rock & debris left by a glacier |
| Types | Lateral, terminal, medial, ground |
| For climbers | A route to/around glaciers |
| Difficulty | Intermediate (loose ground) |
A moraine is a ridge or deposit of rock and debris left behind by a glacier. Lateral moraines run along a glacier’s sides and terminal moraines mark its furthest advance. Mountaineers often follow or cross moraines to access glaciers, where the loose, rubbly ground can be unstable and tiring.
Types
Lateral (sides), terminal (end), medial (merged), and ground moraine — the big ridges are lateral and terminal.
For climbers
Moraines are often the approach route to a glacier; expect loose scree and talus before the ice and crevasses of glacier travel.
Frequently asked questions
What is a moraine?
A moraine is an accumulation of rock, gravel, and debris that a glacier has carried and deposited. As ice flows it bulldozes and transports material, leaving ridges and mounds that record where the glacier has been — a defining feature of glaciated valleys.
What are the types of moraine?
The main types are lateral moraines (along a glacier's sides), terminal or end moraines (marking its furthest advance), medial moraines (where two glaciers' lateral moraines merge), and ground moraine (debris spread beneath the ice). Lateral and terminal moraines are the most prominent ridges.
Why do climbers cross moraines?
Because moraines line and surround glaciers, mountaineers often follow a lateral moraine's crest to approach a peak or cross moraine debris to reach the ice. The loose, rubbly, sometimes unstable ground makes moraine travel tiring and a place to watch your footing.
Sources
- Glacial terrain — American Alpine Club