Meet the Providers

Dr. Laura Peterson, MD

In 2008, Pediatrician, Dr. Laura Peterson, separated from active duty at then Elmendorf AFB, in Anchorage, Alaska, in order to fulfill her, and Dr. Bruce Hess’ vision of forming a pediatric clinic that would serve the children of south-central Alaska.  Dr. Peterson continued service as a flight doctor in the USAF Reserves until retiring in 2014. Dr. Peterson’s robust team has since continued to grow and provide an unsurpassed level of quality of pediatric care to the Mat-Su Valley region.

Dr. Laura Peterson, Pediatrician, Wasilla

Dr. Bruce W. Hess, DO

Dr. Bruce Hess separated from active duty at Elmendorf AFB to join Dr. Peterson as co-owners of Ptarmigan Pediatrics, LLC., in 2009. Like Dr. Peterson, Dr. Hess also served as a flight doctor in the Reserves. He retired in 2015 and they joined forces in opening the clinic as both pediatricians are good friends and hold similar medical philosophies of providing the highest of quality patient care. Dr. Hess hails from New Orleans and his hobbies includes collecting Batman memorabilia.

Dr. Therese Tomasoski, MD

Therese Tomasoski MD is a board certified pediatrician that has been working in the Valley since 2004.  She joined Ptarmigan Pediatrics in January 2015.   After graduating from Michigan State Medical School in 2001, she did her residency at MSU Kalamazoo Center for Medical Studies.  She and her family moved to Alaska from Michigan in 2004 and is proud to call the Matanuska Valley her home.  Dr. Tomasoski is the proud Mom of 3 children, including teenage twins.  She enjoys gardening, Nordic skating and fishing and hiking with her family.  Dr. T enjoys seeing all age groups from newborn to teens, managing acute and chronic conditions and helping families navigate the wonderful but sometimes bumpy road of parenting.


Dr. Marie Westphal, MD

Dr. Marie Westphal joined our practice in March 2015 after retiring from active duty in the USAF at Joint Base Elmendorf/Richardson.  Dr. Westphal, Dr. Peterson, and Dr. Hess were all in the same residency program at Keelser AFB, Biloxi, Mississippi.

Dr. Marta Beaubien MD

Dr. Beaubien graduated from University of Washington and completed her pediatric training at UCSF-Fresno. She joined Ptarmigan Pediatrics from Moses Lake, WA where she enjoyed seeing a wide variety of rural medicine patients. Dr. Beaubien is married and has 2 children. They enjoy hiking, back packing, traveling, and photography.

Dr. Tamara Krimm

Dr. Tamara Krimm, MD

Dr. Tamara Krimm graduated from the University of California San Diego School of Medicine.She then completed her residency in pediatrics at Cook County Children’s Hospital in Chicago. She has been providing care in the Mat-Su Valley for over 20 years and joined Ptarmigan in 2022. She enjoys hiking, reading and knitting.

Dr. Allison McLellan, MD

Dr. Alli is a board certified pediatrician that moved to Alaska in 2021 after completing residency. She made her way gradually north during her career, with the goal of eventually practicing in Alaska. She graduated from University of Central Florida College of Medicine in 2018 and completed residency at Children's Wisconsin/Medical College of Wisconsin in 2021. Dr. Alli loves the outdoors and will take any recommendations you have on fishing, hiking, or berry-picking.


Randall Twenhafel, PNP

Pediatric nurse practitioner, Randy Twenhafel, joined Ptarmigan Pediatrics in December 2010. Nurse Twenhafel served with distinction alongside Drs. Peterson and Hess at Elmendorf AFB Medical Center where he was often the most requested provider. His strong work ethic, excellent bed-side manner and patient care priorities help Ptarmigan Pediatrics meet the immediate needs of a growing patient population.

Jenni Thomas, MSN, CPNP, IBCLC

Jenni graduated with a Bachelor of Science in Nursing from California State University, Chico, and a Master of Science in Nursing with honors from the University of Virginia. She joined Ptarmigan Pediatrics in January 2018 after retiring from nearly 22 years active duty in the United States Air Force.   Jenni chose this community as her forever home specifically to work with her former active duty colleagues Dr. Peterson, Dr. Hess, and Randy Twenhafel.  Jenni is a board certified Pediatiric Nurse Practitioner and International Board Certified Lactation Consultant.  She believes strongly in effective parent and pediatric provider partnerships to further the health of children.  Outside of work, Jenni enjoys time with her family and dog, participating in activities such as K9 nosework and hiking.


Janet Shelley, FNP

Janet graduated as a registered nurse with her BSN in 1992. In 2008, she and her family moved to Alaska. She earned her MSN and Family Nurse Practitioner certification from Graceland University in 2012 and started working at Ptarmigan Pediatrics in 2013. She enjoys spending time with her family and friends, traveling, and fishing.

Chantal Hawk, PNP, PhD

Chantal Hawk, Pediatric Nurse Practitioner joined Ptarmigan Pediatrics in February 2020. She completed her Doctorate of Nursing Practice with the University of Arizona in Tucson. Prior to that, she worked as a registered nurse in the NICU in Anchorage and Omaha, Nebraska. Chantal enjoys connecting with families and building strong relationships with children and their parents. Outside of clinic practice, Chantal enjoys spending time with her husband and children exploring Alaska.


Naomi Johnson, FNP

Naomi Johnson graduated with a Bachelor of Science in Nursing from Berea College in Kentucky. After working as a mother-baby nurse, hospice nurse and a school nurse, she returned to school to become a Family Nurse Practitioner through Frontier Nursing University in Kentucky. She joined Ptarmigan Pediatrics in 2020. Naomi, along with her husband and 3 children enjoyed living overseas for several years. Naomi is fluent in Japanese and can speak some Mandarin as well. Naomi found her passion working with children as a school nurse and now feels blessed to work with kids of all ages as a Nurse Practitioner at Ptarmigan Pediatrics. Naomi enjoys gardening, hiking, skiing and being out in the beautiful Alaskan outdoors.

Desiree Cook, CPNP-PC, PMHNP

I have a deep and abiding passion for children and teen mental healthcare. As an Advanced Practice Nurse; caring for my patients with compassion, integrity and civility are the principles that guide me. I am providing care to both the patient, and the patient’s family. Comprehensive care means I interpret a patient’s overall health through the lens of their quality of life, living situation, environment, culture, and personal relationships. Nursing is more than just science; it is focusing on a deep level of caring in service to our patients.

I had the pleasure of receiving my Bachelors of Science in Nursing from Middle Tennessee State University 2012. I spent the next several years working as a Registered Nurse, learning humility and the importance of leadership and patient advocacy. In 2017, I completed my Masters of Science in Nursing from King University with a focus in child growth and development. During the Pandemic I had the opportunity to further my education into the beautiful complexities of mental health obtaining my post graduate certification as a psychiatric nurse practitioner. I am a nationally certified Pediatric Nurse Practitioner and Psychiatric Mental Health Nurse Practitioner.

Growing up in Knoxville, TN I thought there could be no place more lovely with mountains until we relocated to Alaska in November of 2016. In my spare time you’ll find me with my family at sporting events or enjoying the various adventures in Alaska!