Oct 13 (Reuters) - Canada's British Columbia province on Thursday warned residents to prepare for flooding when rains eventually return after a prolonged drought exacerbated by climate change that has raised concerns about long-term damage to ecosystems ranging from glaciers to salmon rivers. Vancouver, the largest city in British Columbia, received less than a sixth of its average rainfall in August and September and has received only 0.2 millimetres so far in October, according to Environment Canada. Salmon migrate from the ocean to rivers to spawn at this time of year, but this month social media pictures showed thousands of dead salmon in a dried-up stream in central British Columbia. While the dry fall is less damaging than the heat dome that engulfed British Columbia last summer, it is still not good for glaciers' long-term health, said Brian Menounos, a professor of geography at the University of Northern British Columbia. Register now for FREE unlimited access to Reuters.com RegisterReporting by Nia Williams in Revelstoke, British Columbia; Editing by Josie KaoOur Standards: The Thomson Reuters Trust Principles.

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