Increased volcanic activity was observed in December 2020; an effusive eruption formed a new lava dome inside the crater on 27 December.[13][14] Government officials began outreach efforts to residents in the area throughout December and January, in order to review evacuation plans in case volcanic activity at the volcano escalated.[3] The effusive eruption continued into January, during which time the lava dome had grown between 100 and 200 m (330 and 660 ft) wide and 900 m (3,000 ft) long.[15] In February 2021, the lava dome was still actively growing, releasing gas and steam plumes from its top.[16] By 22 March 2021, the lava dome measured 105 m (344 ft) tall, 243 m (797 ft) wide and 921 m (3,022 ft) long.