Impact Statement In October of 2017, Sonoma County, California, experienced devastating and historic wildfires and subsequent community trauma. This manuscript details the development, dissemination, and evaluation of a public mobile mental health app for wildfire survivors. Lessons learned are offered to contribute to the science and practice of using digital tools to conduct disaster mental health outreach and research. In October 2017, Northern California experienced devastating and historic wildfires leaving the community in need of support to foster emotional resilience during the recovery process. Adolescents represent a particularly vulnerable population in the wake of disaster, and digital mental health interventions may hold promise for reaching teens at scale. The present study examined the feasibility and efficacy of a mobile mental health app for disaster, Sonoma Rises. A multiple-baseline single-case experimental design (SCED) utilizing a research-enabled version of the app was employed with seven adolescents who experienced significant damage to their homes and schools in the wildfires. Participants completed daily mood ratings, weekly measures of posttraumatic stress symptoms, internalizing and externalizing symptoms, psychosocial functioning, and then pre-post-measures of anxiety, depression, wellbeing, sleep, academic engagement, and perceived social support as well as quantitative and qualitative measures of intervention satisfaction and feasibility. Sonoma Rises was found to be feasible in terms of engagement, satisfaction, and likelihood of recommending to a friend. During the study, another wildfire occurred and all participants underwent a prolonged mandated evacuation and were subject to a series of extended power outages. Uptake of the publicly available version of the Sonoma Rises app among the general population was modest but engagement among users was sustained. Lessons learned are offered to contribute to the science and practice of building, disseminating, and implementing digital tools to conduct more equitable disaster mental health outreach and research.