Description: From Cameron and others, 2023: "Like in previous years, Iliamna Volcano experienced at least one large avalanche in 2018, as well as many smaller ones. The Aviation Color Code and Volcano Alert Level at the volcano remained GREEN and NORMAL throughout the year. Late in the morning of July 11, a resident from the Kenai Peninsula observed a fresh slide deposit on the east face of Iliamna Volcano. A retrospective analysis of seismic data indicated a probable avalanche signal at 00:24 UTC on July 11, 2018 (July 10 at 14:24 AKDT). The same resident observed a deposit from a slightly larger avalanche on August 1, 2018, but retrospective seismic analysis did not yield a possible signal for this later event. These deposits are very similar to those of Iliamna Volcano avalanches observed in prior years (Cameron and others, 2020; Dixon and others, 2020).
"On September 6, 2018, AVO measured the gas emissions at Iliamna Volcano during its annual overflight. These values proved largely unchanged from those of the previous year: instruments recorded an H2 S/SO2 value of about 2, a CO2 / (SO2 +H2 S) value of about 6, and an SO2 emission rate of 45±30 metric tons per day (t/d). The large uncertainty of the SO2 rate is due to a local wind field around the volcano that produces swirling air currents."