Mattmarksee Reservoir
High-altitude reservoir in Valais, Swiss Alps
A high‑alpine reservoir in Valais created by the Mattmark dam; hikers and mountaineers use the lake as a base for trails and glacier‑edge views in the Alps.
Mattmarksee at a Glance#
Address: Mattmarksee (Mattmark Reservoir), near Saas-Almagell, Valais, Switzerland
Hours: Open access (no set opening hours)
Admission: Free (public reservoir and hiking area)
About 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.
How to Get to Mattmarksee#
Mattmarksee (Mattmark dam) sits in the Saas Valley in Valais near the village of Saas‑Almagell. The usual approach is by road up the Saas Valley from the rail hub at Visp/Brig: drive into the Saas Valley and follow the local road up the valley to the Mattmark dam where there is visitor parking and a short walk down to the reservoir.
Regional PostBus/local buses run from Visp into the Saas Valley to Saas‑Almagell and neighbouring villages; from those stops a short taxi ride or a walk on the local road brings you to the dam.
Best Time to Visit Mattmarksee#
Best visited in summer (June-September) when trails and access roads are most likely to be free of snow.
Weather & Climate near Mattmarksee#
Mattmarksee's climate is classified as Subarctic - Subarctic climate with cold summers (peaking in August) and freezing winters (coldest in February). Temperatures range from -9°C to 13°C. Abundant rainfall (1001 mm/year), wettest in October, distributed fairly evenly throughout the year.
| Month | Comfort | Temp | Feels | Rain | Sky | Humidity | Wind | UV | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | Poor | -9° - -3° | -11° | 74 mm | overcast | 82% | 3.5 m/s | 0.1 low | 8.9h |
| February | Poor | -9° - -3° | -11° | 70 mm | overcast | 82% | 3.5 m/s | 0.3 low | 10.2h |
| March | Poor | -8° - -1° | -10° | 81 mm | partly cloudy | 82% | 3.8 m/s | 0.6 moderate | 11.8h |
| April | Poor | -6° - 1° | -7° | 90 mm | partly cloudy | 81% | 3.9 m/s | 1.0 high | 13.4h |
| May | Poor | -1° - 5° | -1° | 101 mm | overcast | 80% | 3.7 m/s | 1.4 high | 14.8h |
| June | Acceptable | 2° - 9° | 3° | 84 mm | partly cloudy | 78% | 3.5 m/s | 1.7 very high | 15.6h |
| July | Acceptable | 5° - 13° | 7° | 72 mm | partly cloudy | 76% | 3.4 m/s | 1.8 very high | 15.2h |
| August | Acceptable | 6° - 13° | 8° | 82 mm | partly cloudy | 78% | 3.2 m/s | 1.5 high | 14.0h |
| September | Acceptable | 3° - 10° | 4° | 79 mm | partly cloudy | 79% | 3.4 m/s | 1.0 moderate | 12.4h |
| October | Poor | -1° - 5° | -1° | 102 mm | partly cloudy | 82% | 3.5 m/s | 0.5 moderate | 10.7h |
| November | Poor | -5° - 1° | -7° | 90 mm | overcast | 84% | 3.5 m/s | 0.2 low | 9.3h |
| December | Poor | -8° - -2° | -10° | 76 mm | overcast | 80% | 3.6 m/s | 0.1 low | 8.5h |
