Low lake water, dry conditions in Newberry caldera the cause of increased sulfur smells?

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In early- to mid-July, several campers and U.S. Forest Service (USFS) personnel reported occasional strong sulfur smells in the East Lake and Cinder Hill campgrounds located on the shore of East Lake inside the Newberry caldera. In response, scientists with the USGS Cascades and California Volcano Observatories joined with USFS personnel to increase volcanic gas monitoring at East Lake as well as in locations where sulfur smells were reported. No unusual gas emissions have been detected and the USGS and USFS will continue to monitor conditions in the caldera.

A possible explanation for the increase in sulfur smells is that dry conditions and lower lake levels may allow hydrogen sulfide and other gases to reach the surface without first being filtered by lake and/or groundwater. Seismicity and surface deformation at Newberry Volcano remain at background levels so the sulfur smells are not likely due to changes in the Newberry magmatic system.

Field crews have set up temporary gas monitoring sensors and are sampling hot springs and seeps, soils, and areas where sulfur smells were reported. The preliminary data show little change from previous years and a longer-term monitoring effort will help to detect trends.

Gas detection devices have been provided to the USFS and campground hosts that alarm at unsafe levels. If visitors experience strong sulfur gas smells or headaches and burning or watering eyes, they are advised to leave the area and contact USFS staff or campground hosts to report the event.

UPDATE: Field crews have been taking gas measurements at Newberry Volcano. All measurements are within normal ranges, and no new reports of strong sulfur smells have been received since the July 24, 2020 weekend.