Between May and June 2019, an extended sequence of heavy rainfall events over the South Central United States caused historic flooding along the Arkansas River and its tributaries. Major and record river flooding occurred primarily in northeastern Oklahoma, and the elevated flows continued downstream into Arkansas where the caused additional inundation. Antecedent soil moisture levels and water levels in lakes and streams were already high from previous rains, priming the region for significant runoff and flooding. The prolonged combination of high atmospheric moisture and a sustained weather pattern extending across the continental United States led to frequent high-yield rainfall over the Arkansas River watershed. The overarching weather pattern allowed moisture levels to quickly rebound after each sequential rainfall episode. With soils already saturated, the excess precipitation became surface runoff and flowed into the already elevated lakes and streams. Most rainfall occurred in connection with a series of repeated thunderstorms between May 19–21, which was then followed by additional rains that kept streams within flood stage.
Flooding in the Arkansas River basin caused an estimated $3 billion in damage and killed five people. The initial episode of torrential rainfall prompted the issuance of two flash flood emergencies for several counties in eastern Oklahoma on May 20, with numerous water rescues occurring during the event. Several reservoirs in eastern Oklahoma filled over capacity and reached record levels, requiring large releases of water to alleviate the dangerously high storage of water. Repeated rains continued to keep the reservoirs filled, necessitating further releases of water. The prolonged release of reservoir water combined with surface runoff to cause near-record to record flooding along the Arkansas River. Parts of the Tulsa metropolitan area and entire towns near swollen rivers were inundated. In some locations the Arkansas River backed upstream into its tributaries, causing major flooding. The bulge of elevated water levels that began in Oklahoma flowed downstream into Arkansas by May 23, breaching three levees along the Arkansas River and inundating numerous buildings. In Van Buren, the flood was assessed by the United States Geological Survey as a 1 in 200 year flood event.[note 2] Federal major disaster declarations and statewide states of emergencies were declared for Oklahoma and Arkansas.
Date: May 18, 2019–June 14, 2019
Location: Eastern Oklahoma, western Arkansas, southeastern Kansas, southwestern Missouri
Deaths: 5 total
Property damage: $3 billion (2019 USD)