Calgary will soon have a mandatory emergency alert system that pushes a short message to all cellphones in the area, the Calgary Emergency Management Agency chief says.

"This is something that we have been lobbying for, for a long time, and we are excited," Tom Sampson told The Homestretch on Monday.

"Most Calgarians have a cellphone — it's actually apparently 95 per cent — within arm's reach. It allows us to not only to message Calgarians, but also, if you are visiting from Idaho and you are in Calgary, your cellphone will be alerted, also."

This element of the overall emergency alert system — which includes social media and the ability to break into local radio and television broadcasts — is cellphone specific.

"It's known as a cellular push for data, as SMS text message. As long as the person has service in the area, that message would come to any phone that's in the area that is identified. It will pop onto your cellphone as an urgent message. 'There has been an emergency alert issued for your area for the following problem. Please take shelter or do this or that, and potentially go this website for further information.'

"It won't wake a phone that is dead, it will only deal with phones that are on."

Sampson says the service should be online by April, but there's still questions that will need answers.

"Let's say we have a problem in the downtown core and we are advising people to stay away from the core. Can we create a curtain around that area and when you enter that, your cellphone will go off and say, 'You have entered an area where there is an emergency alert.' Those are the questions right now about how the system will work."

The chief says the system will be focused on emergencies that have happened before, so the missile alert mistake in Hawaii recently isn't on their radar.

"Let's talk about things that really will happen," Sampson says.

"Let's say we have a severe storm, funnel clouds in Calgary, or even a touch down tornado, that kind of thing. You would get a message that said, 'it's in this area, please avoid the area, please go to the following website for further information.'

"You are trying to get a very short, clear message out, that this is the danger and here are the basic steps to take, seek shelter."