There are a number groups and communities dedicated roller derby officiating.
Many leagues use Facebook to post updates and opportunities for volunteering and getting experience reffing.
PFM Roller Derby – Seattle-area Recreational Roller Derby PFM, or Potential Fresh Meat is a learning league, and runs learning scrimmages once a month, as well as skills practices. Currently skating at Magnuson Community Center
Facebook: PFM Officials!
Southside Revolution Junior Roller Derby located in West Seattle, at Southgate Roller Rink. Email officials@southsiderevolution.com or visit their Facebook page: SSR Officials & Lead Volunteers
Rainier Roller Riot is located in West Seattle, currently skating at Delridge Community Center.
Facebook: RRR Officials, Volunteers, and Photographers Info Page
Home - Seattle Derby Brats
North Seattle, currently skating Seattle Derby Brats Warehouse: 13024 Stone Ave N, Seattle, WA 98133
https://goo.gl/maps/tWCF7TpbQYrSLK4c6
Email their head ref for more information: headref@seattlederbybrats.com
PNW Roller Derby Events Calendar - Seattle Area (google.com)
This is another site and Google calendar I created to help with scheduling of bouts and to give officials a resource to help with planning their schedules.