How does climate change affect the likelihood of extreme rain? Federal department aims to publish rapid results

A house on a farm is surrounded by floodwaters in Abbotsford, B.C., on Wednesday, November 17, 2021. THE CANADIAN PRESS/Darryl Dyck

Federal scientists will start to publish rapid results looking at how much more likely major rainstorms have become due to climate change.

Environment and Climate Change Canada says it’s expanding its rapid attribution system, so far used to analyze extreme temperatures, to also include extreme precipitation.

Officials say they have already run the tool on 42 extreme precipitation events across Canada since June.

They say the vast majority of those events were up to two times more likely to happen because of climate change, and three were up to 10 times more likely.

The expanded results come as an atmospheric river soaks southern British Columbia, prompting evacuation orders and local states of emergency.

A study co-authored by some of the same federal scientists behind the new tool found the 2021 B.C. atmospheric river was about 60 per cent more likely to happen due to climate change.

This report by The Canadian Press was first published Dec. 11, 2025.

Jordan Omstead, The Canadian Press