Clellan (better known as "Mammie to those who knew her) was born February 26, 1939, in Groom, TX, to Leroy and Nina Terbush. She was a loving daughter, mother, grandmother, and great grandmother. She spent her early years as a telephone operator for Southwestern Bell. Her greatest attribute and calling was caring for her family, and her door was always open for those needing a comforting place to stay. In addition, she found great pride in maintaining her home and lawn.

She was preceded in death by her parents, Leroy and Nina Terbush; and her sister, Leola Dunlap.

She is survived by her brother Gerald Terbush and wife Ann; sister Louise Leach; son Jerry "Pete" Kern and wife Wendy; two daughters, Cindy Walker and husband Cliff, and Gena Seago, all of Amarillo; eight grandchildren, Jeremiah, Trey, Meghan, Dallas, Clenell, Shilo, Rance, and Cydney; and eight great-grandchildren, Jaylyn, Gracyn, Maddox, Mahki, Ayden, Jazzlyn, Adalynn and Jalei.