As the Eaton fire spread, many areas were notified of evacuation warnings and orders well in advance. In the heart of Altadena, where all 17 reported deaths occurred, evacuation orders came hours after fire did.

The investigation is critical for not only understanding what happened, but for ensuring it never happens again, said an attorney for 300 Altadena residents.

When the Eaton Fire broke out, some people who live in Altadena say they never got the order to get out. That's raising concerns about an emergency alert system that was supposed to let residents know when it was time to evacuate.