The article provides information about nival-volcanogenic, possibly glacial-volcanogenic, mudflows (lahars) on three streams on the south side of Atlasov Island (Kuril Islands, Russia). The island is an active stratovolcano Alaid, 2339 m asl high. The effusive-explosive eruption of the Alaid volcano began on September 10, 2022 and continues to the present day. Strombolian activity of the apical cone and lava outflow is observed. Lava filled the summit caldera by September 27. The lava flow then crossed the southern part of the caldera crest and began to descend down the erosional depression at the tops of the catchments of three unnamed streams. Photography and satellite images showed the presence of mudflow transformation of stream beds and slopes, and mudflows fan at the mouths of the streams. Analysis of meteorological and volcanological data showed that the formation of lahars was caused by rapid melting of snow/ice under the influence of lava flow and it occurred between September 29 and October 2.