Others said they didn't see the test at all.
"Did not see it on Comcast in Northern Virginia. Instead, saw about 30 seconds of QVC (was watching MSNBC at test time)," another tweet read.
One reason the alert was not seen by some is that satellite television providers are not yet a part of the Emergency Alert System, FEMA officials say.
It has also been reported that a Lady Gaga song played through the test period for some viewers.
The glitches are just a few of the gaps in a system created almost five decades ago.
Americans used to be able to easily tune in to the Emergency Broadcast System. Every radio dial had a small triangle marking where the public could tune in for a message from the government. Everyone knew about it. How quaint.
From Facebook and Twitter, to cell phones and e-mail, digital communications capabilities of the nation have rocketed ahead even as the US government's Emergency Alert System has remained tied to radio and television technology.
In the wake of 9/11, the move to push into the digital realm – specifically with cell phone and smart-phone alerts – has grown. In 2006, President Bush signed an order to develop "an effective, reliable, integrated, flexible, and comprehensive system to alert and warn the American people ... "
To that end, the new Integrated Public Alert and Warning System (IPAWS) system being developed by FEMA and the FCC will eventually include not only the EAS, but digital capability to send alerts to cell phones, websites and other tools.