Mattmarksee

A high-alpine reservoir in the canton of Valais, created by the Mattmark dam and fed by glacier meltwater. The lake and dam sit above the Saas valley and are visible from nearby mountain roads and trails.

Visitors come for panoramic views of the reservoir and surrounding high peaks, short alpine walks along the shore, and access to nearby glacier landscapes. The dam itself is a prominent engineered feature visible from multiple viewpoints.

The reservoir was formed by construction of the Mattmark dam in the 20th century to impound glacier-fed runoff for hydroelectric use. During construction in 1965, a glacier-related collapse caused a fatal accident that remains a well-known event in the area’s recent history.

Located in Valais in southwestern Switzerland, the reservoir sits above the Saas valley and is reached by road from Saas-Fee and other valley towns. The site is in a high-mountain setting with glaciers and steep ridges nearby.

• Access and viewpoints: Accessible by a mountain road from the Saas valley, with parking and marked paths leading to viewpoints around the reservoir.
• 1965 accident: Associated with a major 1965 construction disaster when a glacier/avalanche collapse killed many workers during dam construction; the event is a significant part of the site's modern history.

What to See #

• Mattmark dam: The Mattmark dam structure at the upper edge of the reservoir, which impounds glacier-fed water to form the lake and supports hydroelectric schemes.
• Shore viewpoints: Walkways and viewpoints on the reservoir shore that offer close views of the dam, the lake surface and surrounding glacier-fed peaks.