Are There Glaciers in Yellowstone National Park? No—But Glacial Landforms Abound

No active glaciers exist in Yellowstone National Park today. The last glaciers retreated ~15,000 years ago (Pinedale glaciation). However, the park is a textbook of glacial landforms:

Visible Glacial Legacies

• U-shaped valleys: Lamar Valley, Hayden Valley — classic glacial troughs.
• Cirques: Amphitheater-shaped hollows at valley heads (e.g., around Mount Washburn).
• Arêtes & Horns: Knife-edge ridges (arêtes) and pyramidal peaks (horns) — e.g., Electric Peak.
• Moraines: Lateral, terminal, ground moraines — ridges of unsorted till marking ice margins.
• Kettle lakes: Depressions from buried ice blocks melting (e.g., many small ponds).
• Erratics: Large boulders transported far from source (e.g., "Glacial Boulder" near Inspiration Point).
• Outwash plains: Flat, sorted sediment beyond terminal moraines (e.g., Madison Valley).

Why No Glaciers Now?

Yellowstone's mean elevation (2,400 m) and latitude (44°N) are below the modern equilibrium line altitude for glacier formation in this continental climate. Nearby ranges (Wind River, Teton, Beartooth) still host small glaciers.

Perennial Snowfields vs. Glaciers

Some high, shaded cirques retain snow year-round (e.g., Northeast face of Mount Washburn). These are perennial snowfields—not glaciers, as they lack sufficient mass/flow.

Climate Change Context

Regional warming reduces snowpack, advances melt. If cooling occurred, cirque glaciers could reform—but current trajectory is opposite.

Yellowstone's glacial past is written in its topography. The ice is gone, but its architecture remains.