How Weather Alerts Work

By: Diane Dannenfeldt

Weather alerts are used for tragedies like the May 12, 2008 earthquake in China.
Weather alerts are used for tragedies like the May 12, 2008 earthquake in China.
Wang Jian/China Fotopress/Getty Images

In China, after an earthquake measuring 7.9 on the Richter scale caused more than 55,000 deaths and billions of dollars worth of damage in May 2008, rivers blocked by landslides threatened to worsen the tragedy with torrential flooding. To prevent further loss of life, local government offices sent emergency text alerts to residents downstream, warning them of the rising waters and urging them to leave [source: Yahoo News/AP].

In Boone County, Ill., an unseasonal tornado surprised Poplar Grove residents in January 2008, flattening four houses and spurring neighboring Winnebago County to adopt a Reverse 911 system that now sends residents alerts of bad weather and other emergencies via landline phones, cell phones, e-mail and voice-over Internet protocol (VoIP) numbers [source: Rockford Register Star].


Loud sirens are increasingly being replaced by the use of digital and Web technology for emergency alerts. Weather alerts provide the warnings we need to head to shore, batten down the house or simply seek shelter. And while a siren may be the first thing that comes to mind as a bad weather alert, emergency alerts can be sent using many different forms of communication. In fact, Internet and wireless technology make it possible to receive emergency weather alerts as notifications on your PC, cell phone or other mobile device.

But what form of emergency alert works best in which situation? And how do you sign up to receive emergency alerts? Read on to find out.

The Emergency Alert System

Hurricane specialist Lixion Avila and forecaster Martin Nelson track Hurricane Ernesto at the National Hurricane Center.
Hurricane specialist Lixion Avila and forecaster Martin Nelson track Hurricane Ernesto at the National Hurricane Center.
Joe Raedle/Getty Images

Maybe you remember hearing a long, shrill tone on your TV or radio, followed by this announcement: "This is a test of the Emergency Broadcast System . . . this is only a test" and then more about the information that would have been provided during an actual emergency.

That system started during the Cold War as a way for the president to reach all Americans during a national emergency. After 1963, it also was used to transmit state and local emergency alerts over local broadcast networks. The Federal Communications Commission (FCC), which oversees the system, required all television and radio stations to play the attention signal and test script at least once a week. And between 1976 and 1996, the system was activated more than 20,000 times, mostly for weather alerts [source: New York Times].


In 1997, the FCC gave the system a technological overhaul and a name change to the Emergency Alert System (EAS). Now the weekly test is a shorter, eight-second digital data signal produced by all AM, FM and broadcast TV stations, as well as cable systems with at least 10,000 subscribers, digital radio and TV and direct broadcast satellite providers. With digital technology, the EAS can pack more information into an emergency weather alert or other announcement, target it to a more specific area and send it out much faster.

Here's how the system handles a bad weather alert. First, the National Weather Service sends out the alert on its NOAA (National Oceanic and Atmosphere Administration) Weather Radio (NWR) signal, which uses specific area message encoding (SAME) and coding protocols similar to the EAS. Next, the broadcast stations' or systems' EAS equipment decodes the NWR signal. After that, the broadcasters can retransmit the weather warning to their audiences, perhaps as scrolling script along the bottom of the TV screen [source: NOAA].

State and local officials also can use the EAS to send emergency information, and the system works in cooperation with the Federal Emergency Management Administration (FEMA). The FCC and EAS make it possible to send a message through the station, cable system, satellite company or other participating service when it's unattended. And messages can be converted automatically into any language the station or system uses [source: FCC].

But you don't need to be watching TV to get weather alerts. You can buy a radio receiver or scanner that can pick up continuous weather watches, warnings and forecasts broadcast on dedicated frequencies by the National Weather Service's all-hazards radio network, NWR. Prices range from $20 to $200, and the units are available through electronics and sport goods stores. Depending on the model, you can choose a receiver that has:

  • A tone alarm to activate the receiver at night when the audio is turned off
  • SAME technology limiting alerts to those within a specific geographic area
  • Battery backup to run the receiver during power outages
  • Vibrations, flashing strobes and warning lights to alert the hearing impaired

[sources: NOAA and NWR]

Maybe you'd prefer to receive weather alerts via your cell phone or mobile device. Keep reading to find out what options are available.

Cell Phone Weather Alerts

Cell phone weather alerts can notify users of impending storms such as tornadoes or hurricanes.
Cell phone weather alerts can notify users of impending storms such as tornadoes or hurricanes.
George Doyle/Stockbyte/Getty Images

Whether you're on your way to a soccer game or waiting to board a plane headed across the country, you'll want to know about problems with the weather at your destination. The easiest way to receive a bad weather alert may be on your cell phone or other mobile device. And you don't necessarily have to pay a premium for weather updates.

Application developers offer cell phone weather alerts ranging from simple weather alerts to notifications that offer broader types of emergency alerts. But media sources, such as The Weather Channel, also can provide an emergency weather alert on your cell phone, often based on reports they've received from the National Weather Service via the EAS. And even some cities are starting to offer these services.


Prices and options vary widely for cell phone weather alerts. Service availability depends on your wireless provider. While some services are free, you'll still need to pay your provider's rate for text messages. Here are some, but certainly not all, of the options:

  • The Emergency Email Network will send free e-mails to your cell phone, wireless device or PC notifying you about homeland security emergencies, local natural disasters, severe weather and other emergencies in your area. All you have to do is provide your ZIP code, e-mail address and device on which you want to receive the messages. You can choose the topic content you want to receive.
  • The Weather Channel provides a variety of weather information, including free 4CAST text-message alerts ranging from severe weather alerts to those specifically for next-day rain, extreme heat, extreme cold, icy precipitation and snow by subscription, as well as on-demand pollen alerts.
  • My-Cast from Digital Cyclone offers forecasts, maps and other weather information, including automatic phone alerts that make your phone beep when storms approach or lightning strikes nearby. My-Cast also brings you weather watches and warnings from the National Weather Service. This is a $3.99 per month subscription service for BlackBerry devices, iPhones and many other phones. The alerts aren't available on AT&T's network.
  • Norfolk Alert is a city-offered emergency alert service. If you live in Norfolk, Va., you can register a valid e-mail address and choose the alerts you'd like to receive, such as inclement weather, road closings and emergency notifications. Alerts can be sent to your home phone, cell phone or e-mail. Other towns also offer this type of service, so check what's available locally for you.
  • WeatherBug Protect from WireFly delivers severe weather alerts and daily forecasts to BlackBerry devices and other cell phones for $2.99 per month. The notification service pinpoints the subscriber's cellular location and gives any alerts for that location. Alerts can be formatted as recorded voice, text message or e-mail. Two-way messaging gives the subscriber a way to respond and report back personally on weather conditions.

Finally, if you're looking for weather alerts about somewhere more distant -- check out NOAA's Space Weather Prediction Center. You can sign up for free e-mails that'll alert you about comets, asteroids, geomagnetic storms, radio blackouts and more.

Wouldn't it be great if the National Weather Service could send weather alerts as text messages directly to cell phone users? That's in the works. Go to the next page to find out more.

FCC Emergency Text Messaging

The federal government plans to send out emergency alerts.
The federal government plans to send out emergency alerts.
© Ron Levine/Photographers Choice/ Getty Images

While the National Weather Service's radio network is a great way to get bad weather alerts straight from the source, you're not always near one of the radio receivers that can pick up the emergency weather alert. And while you can subscribe to a cell phone service for emergency alerts, often the company is simply transmitting information from the EAS. If weather warnings came directly to you as text message alerts, you could receive them right away wherever you were.

The FCC and FEMA are working to make the emergency alerts that come through EAS available in that way and more. While information sent through EAS is currently only available on radios and televisions, the plan is to create a system that can send audio, video and text messages to landline phones, Web sites, e-mail accounts and cell phones [sources: NOAA and RCR Wireless News].


The FCC approved a plan in April 2008 to send emergency alerts to cell phone users. Here's how it would work. A federal agency would be appointed to create the messages and send them to participating mobile providers. (While these providers are not required to participate, T-Mobile, Verizon, Sprint, Nextel and AT&T have said they would participate.) The mobile providers would then send the messages to their subscribers. Similar to the companies themselves, cell-phone users could say they did not want to receive the messages.

The alerts could be triggered by any of these events:

  • A disaster, such as a terrorist attack, endangering Americans' health and safety
  • Weather and other natural disasters, such as hurricanes, tornadoes, earthquakes or severe storms
  • Child abductions, resulting in an Amber alert

Once the message-sending federal agency is appointed, the participating mobile providers would have 10 months to meet the requirements of the new system. They would, for example, be required to make the alerts accessible to people with disabilities by providing a distinct vibration cadence or sound cue to signal emergency text messages.

The so-called commercial mobile alert system (CMAS) for all Americans is required by the Warning, Alert and Response Network Act, which Congress approved in October 2006. However, a nationwide mobile alert system is not expected to be in place until sometime in 2010 [source: FCC Commercial Mobile Service Alert Committee].

For lots more information about weather alerts and related topics, check out the links on the next page.