A flood warning is in effect for Kittitas County, Washington, until 5 PM PDT Sunday due to snowmelt and previous heavy rainfall. Rivers, creeks, streams, and low-lying areas are experiencing flooding, with specific waterways like Little Creek, Spex Arth Creek, Peterson Creek, Big Creek, Cle Elum River, Yakima River, and Tucker Creek being affected. Areas such as Elk Meadows and Easton are particularly impacted by high water levels.