Gas sample expedition to Sherman Crater

Sherman Crater courtesy Google Earth. Click to enlarge. We sampled the labeled fumaroles.

A new round of fumarole gas sampling was made July 24. This year’s crew consisted of Peter Kelly (USGS- Cascade Volcano Observatory) and MBVRC volunteers Dave Tucker, Melissa Park and Lora Beatty.

Crew on the crest of Railroad Grade approaches camp. Black Buttes behind.

We hiked through a very snowy landscape Saturday. The Park Butte/ Railroad Grade trail across a soggy Schreiber’s Meadow is still covered with snow for much of its length– the bog marigolds are in full bloom and liven up the soggy landscape. Once across Rocky Creek (no bridge, high water) the switchback trail up to Morovits Meadows is only partly snow-free. Morovits Meadow itself is completely covered with snow– only the extreme crest of Railroad Grade moraine is snow-free. The valley of Rocky Creek below the Easton Glacier is plugged with snow- not a rock showing, and the glacier terminus itself is indistinguishable among the snowfields.

West Rim fumaroles. Lora and Dave sample gases. Peter Kelly photo.

We headed up the mountain Sunday AM. Not exactly an alpine start, but it was at least not too long after the crack o’ dawn. Many people preceded us– Melissa counted 41 climbers at one time draped across the Roman Wall, far above us as we roped up and ascended Easton Glacier, sans crampons. We tried to enter Sherman Crater via the West Rim, but the loose talus was discouraging, so we backtracked and crossed the South Rim between Pooch Peak and Sherman Peak. Snow covered the entire outer slope of the South Rim, almost completely burying Gravity Rock (site of gravimeter readings and the former location of a short-term seismometer). We just stepped over the rim and hiked down the smooth snow to the fumarole fields on the west side of the crater.

Sulphur crystalizes from the fumes onto rocks of the crater. Peter Kelly photo.

WWU Geology student Lora Beatty collects gas in Sherman Crater.

The fumaroles on the barren talus and clay slope inside the west rim were hissing and spitting. Lots of melting water from a snow patch above. Little springs bubbled among the rocks. Bright yellow sulphur crystals encrusted some of the rocks. We worked in the wet steam, which was only mildly gassy-smelling: masks were not needed. Lora and Dave collected gas samples from three fumaroles, while Melissa and Peter took temperatures at a number of others. Peter had also packed along a new gas sniffer, which just sits on the ground and measures ambient CO2 and H2S. All the while, snow avalanches descended the steep slope below the summit plateau into Sherman Crater– far from us so we could just enjoy the show.

We descended the soft snow on the glacier in the glaring heat, and returned to Bellingham in the early evening– in time for dinner at Boomer’s Drive In.

Peter Kelly built this 10-pound gas sniffer. The small intake is on the right. The box contains a battery, and H2S and CO2 detectors. Data is stored on a small chip.

Glass gas flask. Fumarole gas enters from left in the flex tubing, condenses in the flask (sitting in snow). Once sufficient gas condenses, the flask's valve (top) is closed.

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