- ShakeAlert alerts can reach phones seconds before strong shaking; there is no app called ShakeAlert.
- A Red Flag Warning means critical fire weather is happening or about to.
- Keep a battery radio: most L.A. TV and FM signals come from the same mountaintops.
Los Angeles faces two hazards that can arrive with almost no warning: earthquakes and fast-moving wildfires. The systems that warn you are different for each, and knowing how they work makes the seconds or minutes they buy more useful.
Earthquakes: ShakeAlert
ShakeAlert is the earthquake early warning system managed by the U.S. Geological Survey. USGS says it detects significant earthquakes quickly enough that alerts can be delivered to people and automated systems potentially seconds before strong shaking arrives, and that it serves more than 50 million residents and visitors in California, Oregon and Washington. It is the nation’s only public earthquake early warning system.
How to get ShakeAlert on your phone
USGS lists several cost-free ways:
- Wireless Emergency Alerts: the setting may be under Emergency Alerts or Government Alerts on your phone.
- Your phone’s operating system: Android and iOS have built-in earthquake early warning alerting.
- The MyShake app, from the App Store or Google Play. USGS notes there is no app called ShakeAlert to download.
When you feel shaking or get an alert, USGS says to immediately Drop, Cover and Hold On, or take another protective action depending on your situation.
Tip: Practice Drop, Cover and Hold On with your household once. When an alert arrives, there is no time to think about what to do.
Wildfires: Red Flag Warnings
The National Weather Service issues Fire Weather Watches and Red Flag Warnings. A Fire Weather Watch means critical fire weather conditions are possible but not imminent. A Red Flag Warning, issued with land management agencies, means critical fire weather is ongoing or expected shortly. These warnings are about conditions, not a specific fire; evacuation orders come from local authorities.
How warnings reach you
| System | What it carries | How you get it |
|---|---|---|
| Wireless Emergency Alerts | Imminent threats, AMBER Alerts, public safety messages, ShakeAlert-powered alerts | Automatically on WEA-capable phones in the area |
| Emergency Alert System | Warnings that interrupt TV and radio | Any broadcast station, cable or satellite service |
| NOAA Weather Radio | Weather Service warnings around the clock | A weather radio; L.A.’s KWO37 broadcasts on 162.550 MHz from Mount Lukens |
| Local TV and radio news | Details, maps, road closures | Antenna, radio or streams |
Under the FCC’s rules at 47 CFR Part 11, AM, FM and TV stations, cable systems and satellite services all take part in the Emergency Alert System. Under 47 CFR 10.280, phone carriers may let you opt out of some alert classes, but not National Alerts.
Why Mount Wilson matters during fires
When the 2009 Station Fire approached Mount Wilson, NBC4 and ABC7 reported that nearly all of the 22 Los Angeles TV stations transmit from Mount Wilson and nearby peaks, and more than two-thirds of the region’s FM stations broadcast from there too. Firefighters protected the site, and again during the 2020 Bobcat Fire, when CBS Los Angeles reported crews defending towers valued at about $1 billion. A fire on the mountain could knock many stations off the air at once, which is one reason to keep more than one way of getting information.
A household plan
- Turn on emergency alerts on every phone, and install MyShake if you want an extra source.
- Keep a battery radio and know KNX 1070, which calls itself SoCal’s 24/7 news connection.
- Keep a NOAA Weather Radio for the warnings it carries around the clock.
- Know your evacuation routes, and have a go-bag ready during Red Flag Warnings.
After the alert
Alerts tell you something is happening; local newscasts tell you where and what to do. For free ways to watch, see How to Watch Los Angeles Local News Without Cable. For traffic and road closures during an evacuation, see L.A. Traffic Reports on the Radio, and the Official Tools That Back Them Up.
Practice and preparation
Alerts only help if you know what to do with them. Practice Drop, Cover and Hold On with everyone at home. During Red Flag Warnings, keep your car’s fuel tank full, charge phones and power banks, and keep important documents and medicines ready to grab. If you have pets, plan how you would take them with you.
Check your phone’s emergency alert settings once a year, and make sure older relatives’ phones have alerts enabled too. If you rely on MyShake, open it occasionally so its location settings stay current.
After a large earthquake or during a fire, expect aftershocks, road closures and changing conditions for days. Keep listening to local news, follow instructions from officials, and check on neighbors, especially older people living alone, who may not have received or understood an alert.
Finally, remember the Emergency Alert System works even when you are not looking at a phone. A car radio or a TV left on will carry the alert, which is one more reason to keep a battery radio within reach.