Volcano Record

Mount St. Helens

Mount St. Helens is a Cascade Range stratovolcano whose modern form is defined by a breached crater, debris-avalanche terrain, ash deposits, and lava dome growth.

Why This Record Matters

A volcano reshaped by collapse

The mountain is a clear record of how eruption, flank failure, blast deposits, and dome building can rapidly remake volcanic terrain.

TypeCascade stratovolcano

A volcanic cone in the Cascade arc.

LandformBreached crater

Collapse opened the summit toward the north.

MaterialsAsh and debris deposits

Explosive and avalanche material shape nearby terrain.

ProcessLava dome growth

Post-collapse eruptions rebuilt part of the crater floor.

Overview

What Mount St. Helens is

Mount St. Helens is a volcano in the Cascade Range of the Pacific Northwest. Its current profile records flank collapse, explosive eruption, and later dome-building activity.

The page belongs in the volcano archive because crater form, blast deposits, debris fans, and lava dome growth are all visible parts of one volcanic system.

Landform

Crater breach, avalanche surface, and dome

The north-facing breach and hummocky debris-avalanche terrain show how the cone changed during collapse. Inside the crater, lava dome growth records renewed eruption after the main failure.

Crater

Open summit basin

The breached crater exposes the mountain's disrupted interior.

Apron

Debris-avalanche deposits

Collapsed material spread across the surrounding lowlands.

Arc

Cascade setting

The volcano belongs to a chain of subduction-related peaks.