Ari Montgomery Michelsen, 63, of El Paso passed away on September 28, 2017, after a lengthy illness. He was born August 10, 1954, in Oslo, Norway, to Frances (Blumve) and Arve Michelsen. The family returned to the US while he was a toddler, landing in Maryland where Ari graduated from high school. He received a B.S. in Conservation and Resource Management from the University of Maryland in 1976, followed by his M.S. (1983) in Economics and Ph.D. (1988) in Agricultural and Resource Economics from Colorado State University. Ari was a leader in the field of water resources. He worked for several western universities, most recently as Resident Director of the Texas A&M AgriLife Research Center in El Paso. He took great pride in serving on the board of directors for professional organizations and providing consulting expertise to national and international agencies. These activities gave him the opportunity to travel to places like China, Russia, and Chile. In the midst of his professional success, colleagues also remember his mentorship and kindness. With a Norwegian father and a Californian mother, Ari loved both skiing and the beach. Many summers while growing up were spent with his cousins in Laguna Bay, California. While living in the west, he skied, fished, and camped as often as he could get away. He especially loved sharing these passions while vacationing with his family. Ari is survived by his parents, Arve and Frances Michelsen of Silver Spring, Maryland; his daughters Sonja Michelsen of Omaha, Nebraska, and Anna Michelsen of El Paso, Texas; his sister, Anne Marie Michelsen and sister-in-law, Sandy Stillwell of, Westminster, Maryland; and former wife, Miriam Cook of El Paso, Texas. A memorial service will be held in El Paso in January. Donations and memorials can be made to the American Water Resources Association, Herbert Memorial Scholarship, P.O. Box 1626, 4 West Federal St, Middleburg, VA 20118, awra.org or The Nature Conservancy, https://www.nature.org.