BRITISH COLUMBIA HAS SEEN WORSE DROUGHTS: “We can reasonably anticipate that droughts worse than anything we’ve reconstructed in the past 350 years will be happening in the coming decades,” stated paleoclimatologist Bethany Coulthard when she published the results of her tree ring research in March 2016
Note to Reader:
By analyzing tree rings, researchers are able to peer further back into B.C.’s water history than the existing records. Shallower tree rings reveal years of more extreme summer drought, said researcher Bethany Coulthard in a 2016 interview by CBC News. Using 350 years of tree ring data as well as long-term drought records, Coulthard found at least 16 historical droughts worse than the benchmarks used today by hydrologists and water managers in coastal BC.
It is timely to bring her work forward when British Columbia is again faced with a drought summer following extremely low snowpack levels in the regions where most of the population lives. For context, read STATE OF WATER IN BRITISH COLUMBIA: “Water insecurity is one of the most pressing challenges facing our province, with communities lurching from one water emergency to the next,” wrote Vickey Brown and Tricia Brett in a Vancouver Sun op-ed (June 2026).
B.C. has seen worse droughts than previously thought, tree rings reveal
“Recent streamflow droughts in south coastal British Columbia have had major socioeconomic and ecological impacts. Increasing drought severity under projected climate change poses serious water management challenges, particularly in the small coastal watersheds that serve as primary water sources for most communities in the region,” wrote Bethany Coulthard in the summary to her co-authored published by the Journal of Hydrology in March 2016.
“A 332-year dendrohydrological record of regionalized mean summer streamflow for four watersheds is analyzed to place recent drought magnitudes in a long-term perspective. We present a novel approach for optimizing tree-ring based reconstructions in small watersheds in temperate environments, combining winter snow depth and summer drought sensitive proxies as model predictors.”
“The model is particularly accurate at estimating lowest flow events, and provides the strongest annually resolved paleohydrological record in British Columbia. The extended record suggests that since 1658 sixteen natural droughts have occurred that were more extreme than any within the instrumental period.”
“We have underestimated both how common and how severe the worst droughts are in this part of BC. If we don’t implement more conservative mitigation strategies, the region will be seriously underprepared when one of these droughts hits. The impacts would be disastrous for stream ecology and salmon,” concluded Bethany Coulthard in an interview titled The tale the trees tell: droughts will be worse in BC.
To Learn More:
To read the complete story posted by CBC News, download the PDF of B.C. has seen worse droughts than previously thought, tree rings reveal.
To read an overview the paper published in the Journal of Hydrology, download the PDF of Is worst-case scenario streamflow drought underestimated in British Columbia? A multi-century perspective for the south coast, derived from tree-rings.
A large tree section from the tree ring lab (image credit: UVic News Archive)