Study: Warmer weather will increase flooding in the Columbia River Basin this century Monica Samayoa Warmer winter weather, more rainfall and less snow will contribute to significantly increased flooding in the Columbia River Basin this century due to climate change, new research says. New modeling shows an increase of flooding by up to 60% in the next 50 to 100 years, according to a study by Oregon State University’s Oregon Climate Change Research Institute. Less precipitation falling as snow during the winter will lead to earlier spring streamflows for many rivers in the basin, including the Columbia, Willamette and Snake rivers and hundreds of tributaries.