Board of Directors
Maryann McMahon, OP, President
Sister Maryann McMahon is president of the Racine Dominicans. A nurse practitioner with MSN and FNP degrees from the University of Wisconsin-Oshkosh, she has served in multiple capacities.
Before her election as president of her community, she was the Executive Director of HOPES Center, serving mental health and social service needs of Racine’s poor and homeless.
Agnes Johnson, OP, Vice President
Sister Agnes Johnson holds a B.S. in medical technology from Dominican College, Racine, and an RN from Deaconess Hospital in Milwaukee. She has served as vice-president of the Racine Dominicans. Before being elected to leadership in her community, she was an RN case manager for Home Health United in Portage, a nonprofit health care agency.
Shari Geertsen, Secretary/Treasurer
Shari Geertsen has been the Chief Financial Officer for the Racine Dominicans since 2002. She holds a B.S. degree in Business Administration and Accounting from the University of Wisconsin-Parkside. She also serves on several non-profit boards and is a trustee for three other congregations. She is a member of WICPA, RCRI and WITRI.
Her prior work includes Controller and Accounting Manager in for-profit corporations for more than 10 years.
Joanne Armatowski, SSND
Sister Joanne Armatowski holds a BA in Education and MAs as a Reading Specialist from Cardinal Stritch and Health Care Administration from Marquette University. She held numerous leadership roles in education as a teacher and principal, SSND Community Leadership for 16 years, and health care ministries, including administration of the School Sisters of St. Francis facility in Campbellsport and Notre Dame of Elm Grove.
During her time in community leadership, she was instrumental in the building of Our Lady of Angels, a facility sponsored by the School Sisters of St. Francis and School Sisters of Notre Dame. It is a facility for religious Sisters needing memory care. She has been involved in strategic planning in her community and now with the Racine Dominicans. Sister Joanne has been privileged to serve on boards in both education and health care, most recently on the Our Lady of the Angels Board.
John Crimmings
John Crimmings holds a B.S. degree in Business Administration from Marquette University. John has spent the last 49 years in the real estate business in the Racine area. John was co-owner and President of N. Christensen & Son Real Estate until its merger with The First Weber Group. John then served as Vice President and General Sales Manager of the First Weber Racine office. John has been active with many local non-profit boards over the years, including the St. Catherine's High School Corporation Board, Racine County Economic Development Board, The Racine Community Foundation and several others. John retired from his office manager position in 2025 and remains an active real estate salesperson for First Weber.
Bernadine Flores, NP
Bernadine Flores is a Nurse Practitioner specializing in Geriatrics. She has a Bachelor's in Nursing from Marian College, Fond du Lack, and a Master's Degree in Nursing (specializing in Geriatrics) from Concordia University, both in Wisconsin. She is a Board Certified Geriatric Nurse Practitioner and certified by the American Nursing Credentialing Center. She is also State Certified in wound care, focusing on prevention, treatment and healing of all wound types.
Bernadine has worked with diverse populations in the setting of acute hospitals, public health, medical clinics, nursing homes and her practice in correctional healthcare. She also assists with the Pastoral Wellness Program for St. Mary's Catholic Church. She has participated in numerous Mission Trips, locally and abroad, to provide healthcare to the impoverished and underserved populations.
Robert N. Miller
Robert N. Miller is a native of Mount Pleasant and a retired teacher and administrator from St. Catherine’s High School. He has a lifelong connection with the Racine Dominicans as a student, teaching colleague and lay Associate. He also had extensive experience in his family's golf recreation business and has served as an elected member of the Racine County Board since 1990.
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Susan Boland, Executive Director (ex officio)
Susan Boland has been the Executive Director for Siena on the Lake since October 2018. She holds a BS in Nursing from St. Xavier University and an MS in Nursing from Rush University.
Susan serves on several non- profit boards within the community. Prior to joining Siena on the Lake, Susan served in multiple leadership roles for 23 years within Wheaton Franciscan Healthcare – All Saints and retired as the President of Ascension – All Saints in 2017.
Alex Ostrov (ex officio)
Alex Ostrov has worked in multiple capacities since joining the organization in 2016, currently serving as Accounting Director for the Racine Dominicans. He holds a Bachelor of Business Administration in Accounting from the University of Wisconsin-Milwaukee.
Through his service to various non-profits in southeastern Wisconsin, he brings over a decade’s worth of financial experience to Siena on the Lake.