These sites are often subject to deep winter snow accumulations and recurrent avalanches. The soils exposed by avalanches provide an ideal seedbed for Sitka alder seeds. Once established, its resilient wood, bowed growth form, and ability to resprout if stems are broken allow Sitka alder to withstand repeated avalanche destruction, which would normally kill other plants. Other Sitka alder communities appear to be stable and long-lived and are apparently midseral or even climax. The staminate catkins of Sitka alder are produced during the preceeding growing season, and are exposed during the winter.
Leaves remain green until they are dropped in the fall.