NEW: Central US Winter Storms February 2021 UPDATED: Arctic Amplification UPDATED: Winter Storm Risk Increase Graph: Arkansas River at Van Buren, May 29, 2019 by National Weather Service Near the Oklahoma border at Fort Smith, Arkansas (population 300,000), the river rose to two feet above its previous all-time high on Tuesday morning, May 28. Go to Site Related Events Mississippi River Valley Floods 2019