The dead of night was punctuated by a shrill war-submarine-like alarm, startling even the deepest of Santa Clarita Valley sleepers.
Those jolted awake early Monday morning — not by an earthquake but by their smartphones — can thank the National Weather Service for their courtesy wake up call.
At 1:39 a.m., wireless phones near recently burned areas emitted a combination of five long and short piercing audible tones.
If the early morning alert didn’t wake you up, you’re either a heavy sleeper or you didn’t fall within the area specified by the weather service for a flash flood warning.
Phones impacted by the alert displayed an emergency alert notification which read “Flash Flood Warning this area ‘til 2:30 AM PST. Avoid flood areas. Check local media.”
The system which triggers the warning is the Wireless Emergency Alert public safety system managed by the Federal Communications Commission. A partnership between the FCC, the Federal Emergency Management Agency and wireless carriers makes possible the network functions that relay messages between government agencies and the public.
“Pre-authorized national, state or local government authorities may send alerts regarding public safety emergencies, such as evacuation orders or shelter–in-place orders due to severe weather, a terrorist threat or chemical spill” to the public via the wireless alert system, FCC documents state.
Amber Alerts now use the same system, which is not designed to and does not track the location of any phone using GPS.
How it works
Bundled as small chunks of data, emergency notifications are broadcast from agencies to cell towers servicing zones under imminent threat to public safety.
From those signal towers, the bits of information hits each connected wireless device.
For example, early Monday morning, a storm system threatened to bring a large influx of water to flood and mudslide prone areas.
The system was activated by the National Weather Service shortly before 1:30 a.m. when the cluster of clouds were set to bring the most precipitation.
Phones near the Sand, Calgrove, Sage fire burn areas were alerted — much to the dismay of many people hoping to snooze under the pitter patter of nighttime rainfall.
“My husband who is a deputy jumped up thinking it was his alarm for work,” one Facebook user in the SCV Emergency Now community group said.
Some users thought enabling their smartphone’s ‘Do not disturb’ mode, which silences all non-alarm clock notifications would secure them a good night’s sleep.
Much to their surprise, the system overrode the feature.
“I thought putting my phone on do not disturb would avoid that sort of thing,” another user in the same social media forum posted.
Enabling and disabling the alerts
There’s a silver lining for those who do not want to receive the alerts. Below are instructions to disable the system.
If you choose to disable the feature, you may not receive emergency notifications.
iPhone (iOS 9 and 10)
- Go to Settings.
- Open the Notifications menu.
- Scroll to the bottom and toggle the radio sliders to enable or disable the function.
Android (6.0 and newer)
- Go to Settings.
- Search for “Cell Broadcasts.”
- Toggle radio sliders to enable or disable the function.