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Paleofloods in the Red River Basin
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Climate Change in Southern Manitoba
The climate of southern Manitoba has been much more variable in the recent past.
Although intuition suggests that extreme floods would be more common under a wetter climate, specific climatic thresholds leading to shifts in regional flood hazards are difficult to determine. Estimated annual precipitation inferred from tree rings indicates that southern Manitoba’s hydroclimate has been relatively stable over the last two hundred years. Although this stability was interrupted briefly by pronounced wet intervals in the late 1820s and 1850s, conditions were much more variable and persistent prior to A.D. 1790.
The Red River basin experienced extremely dry conditions between A.D. 1670 and 1775, with below normal precipitation occurring approximately two years out of three. Comparisons with limnological records from North Dakota and Minnesota suggest that the entire northeastern Great Plains were dry for nearly one hundred years around AD 1700. If a similar event were to occur in the future, it would likely have a considerable impact on agricultural production, groundwater supplies and regional hydroelectric potential.