Description

A wet snow avalanche (slush flow / “Murgang”) occurred on 31 March 2026 at approximately 16:00 local time in the Sturmingen Runse above Ennenda (Glarus, Switzerland). The photos (NIKON D7500) were recorded at the end of the avalance with coordinates 47°02'21.23"N 9°04'52.86"E.

At the time of the event, the road toward Ennetbergen was no longer passable for vehicles due to snow conditions, although pedestrian passage remained possible.

Atmospheric pressure was measured using a precision mercury barometer (Lambrecht Fortin-type) at an elevation of 504.4 m above sea level. The observed value was 724.0 mm Hg, with an instrument correction of +0.15 mm, resulting in a corrected pressure of 724.15 mm Hg (~965 hPa station pressure). Reduction to sea level yields approximately 1015–1018 hPa, indicating stable atmospheric conditions.

Visual observations document partial snow cover, active melt conditions, and low cloud ceiling with high humidity. These observations support the interpretation that the avalanche release was primarily driven by thermal weakening of the snowpack.

Instrument

Atmospheric pressure was measured at around 15:50 o'clock using a precision mercury barometer (Fortin-type) and photographed around 17:25 o'clock:
- Model: Quecksilberbarograph 604
- Serial number: 350.226
- Manufacturer: Wilhelm Lambrecht KG, Göttingen (Germany)
- Distributor / calibration: Krüger + Co, Degersheim SG (Switzerland)
- Retail label: Kochoptik, Zürich

The instrument includes an adjustable cistern, vernier scale, and integrated thermometer.
Manufacturer-stated correction: +0.15 mm Hg.

Photos were taken with NIKON D7500.

Snow Line and Weather Conditions

On 31 March 2026, snowfall occurred during the morning hours. The snow line was observed at approximately 600 m above sea level based on visual inspection of the Glärnisch massif.

At the observation site (504.4 m a.s.l.), snowfall was initially observed but melted upon reaching the ground, indicating temperatures near or slightly above 0 °C.

These conditions indicate a rain–snow transition zone just above the valley floor, with ongoing snowmelt at lower elevations.

Air Temperature

The integrated thermometer of the barometer indicated an air temperature of approximately +2 to +3 °C at 17:25 local time, measured indoors within a shed at the observation site (504.4 m a.s.l.).

This measurement was taken approximately 1.5 hours after the avalanche event and at a distance of ~700 m from the release area.

Given the indoor measurement conditions and timing, the outdoor air temperature at the time of the event (~16:00) is estimated to have been close to 0 °C, likely in the range of 0 to +2 °C.

Keywords

wet snow avalanche, slush flow, barometric pressure, mercury barometer, Alps, Switzerland, Ennenda, snowmelt