Residents can register multiple cell phone numbers and email addresses with San Diego County's Reverse 911 system called Alert San Diego. Alert San Diego will provide emergency alerts, including evacuation notices, to your cell phone and email address. This will be in addition to the land line calls that will also be made. To register your cell phone or email address, please visit the Alert San Diego website. It will take up to 24 hours for a newly registered cell phone number or email address to be updated into the system.