Seattle’s Office of Emergency Management runs the Auxiliary Communications Service. Its volunteers support government operations and neighborhoods during an emergency. The city’s volunteer page says ACS is currently the program it is recruiting for.
The ACS site has an application form, a weekly nets page, public event support such as Field Day, and exercises such as its catastrophic communications exercise. An amateur radio license is needed for most roles.
Volunteers serve through the program, not on their own: register as an emergency worker through the sponsoring agency before you help in an emergency.