Many cell owners were surprised and wondering how the alert showed up on their phones.
Luis Ruiz, 47, of Orlando got simultaneous alerts on his work and personal phones. About to head outdoors for a workout, Ruiz appreciated the heads-up: "I knew it was raining, but I didn't know there was a tornado warning."
Phones from Sanford to Walt Disney World sounded off as part of the federal government's Wireless Emergency Alerts system set up in 2012 for Amber Alerts and warnings about terror threats, chemical spills, tsunamis and potentially deadly weather.
It's meant to be used sparingly, said Chuck Hagen, logistics chief with the Florida Division of Emergency Management. "We don't want to be lighting phones up every 10 minutes."
The alerts are not text messages or emails. They have their own format, cannot be replied to and arrive with their own tone and vibration pattern. There's no charge for them.
Customers can opt out of receiving them — except for alerts issued by the president — by poking around in a phone's settings.
The voluntary program has been ramping up gradually among carriers and cellphone makers.
Scott Spratt, forecaster at the National Weather Service in Melbourne, said that during his talks for public audiences, he asks for a show of hands of those who have gotten WEA alerts.
In 2012, one or two hands would go up, Spratt said, but by late last year, as many half of those in audiences said they had gotten one of the notices.
"The numbers are increasing, but it's not universal yet," he said. "It should be by the end of the year."
For years, the Emergency Alert System has delivered emergency information, breaking in on television programming with the sound of anguished buzzing. Alerts are broadcast by NOAA Weather Radio, and private messaging is increasingly popular. Getting alerts on cellphones is the next logical step.
Orlando residents Kirsten Vaughan and her husband were in Denver on Saturday when their phones blurted out tornado warnings from Central Florida. Her phone's alert was from an Orlando television-station app. His was from the iPhone app MyRadar.
But drawing the most attention to Saturday's precarious weather were the cellphone alerts sent by the WEA system.
The previous tornado warnings for Central Florida were March 24 and April 14 last year, when the system didn't have the presence it has today. Spratt said since then, phone-service carriers have gone through surges of expanding WEA capability.
And phones that weren't initially programmed to receive WEA information are getting updates to receive the alerts.
AT&T is able to send WEA messages to 33 models of phones. The company says on its website that it is working to bring more phones into the system: "Please check back regularly to see if your smartphone has been added."
Other carriers, including Sprint, T-Mobile and Verizon, provide similar information on their websites.
The WEA system also doesn't care what a phone's area code is; alerts are sent from cell towers in areas in harm's way to all phones capable of hearing them. That's why out-of-state tourists at Central Florida theme parks got the messages Saturday.
If somebody driving along a highway enters a danger zone after a warning was initially sent out, the driver will still get pinged with a WEA message waiting in a queue.
Robert Campbell, 62 and recently homeless, was surprised Saturday to find his phone that he rarely uses going off with a storm alert. He hurried back to a shelter, which is normally closed during the day but opened its doors.
AT&T spokeswoman for Central Florida, Rosie Montalvo, got her first experience with a WEA alert. She and her husband were waiting for an oil change when her phone and her husband's two phones spoke up in unison.
They skipped the auto service and drove straight home, seven minutes away.
©2014 The Orlando Sentinel (Orlando, Fla.)
