Experts say getting real time information to city residents during an emergency is critical to helping them make the right choices so they can survive a natural or man made disaster that can crop up with little warning.

The tornadoes that hit the city last weekend demonstrated how the city’s emergency communications system can work to do just that, according to OEM Commissioner Joseph Bruno.

A woman in Canarsie, Brooklyn got a broadcast message over her cell phone warning her about the possibility of tornados striking in and around her neighborhood. Bruno said she was able to brace herself just before the twister hit and took off the roof of her home.

"She told me she couldn't believe it. She got this alert. It came through and it really told her what was happening and than she felt the pressure of this tornado coming over her trying to pull her out the door. It was pretty dramatic," Bruno said, saying he felt good that the system worked the way it was designed to.

If the tornados showed the system at its best, the September 11 attacks highlighted the deficiencies with the city’s emergency communications system, which New York has sought to fix over the last decade.

Last year, federal officials and Mayor Michael Bloomberg launched a pilot project, called The Personal Localized Alerting Network, that uses cell tower broadcasting to send emergency messages in real time to cell phones configured to receive the alerts.

The PLAN can be used to send out amber alerts, significant weather alerts or other significant threats to life or property.

"The good part about that is that ever cell phone now being manufactured now has that," Bruno said. "The bad part is that there are a lot of cell phones out there that are older and may not have it. But the way the industry looks at it is every couple of years you have almost a total rollover of cell phones. So in a couple of years you will have everyone on it."

But when it comes to emergency communications Bruno said redundancy is critical. That’s why he urges  people to sign up for the City’s Notify NYC system, which provides real time alerts on a variety of conditions from health notices and school closures to water quality bulletins and emergency parking suspensions.

So far, 93,923 users have signed up for the Notify NYC alerts.