IPAWS, CMAS, PLAN, WEA and COG are all explained in a podcast.
My current Eric's Corner Column in Emergency Management Magazine is Emergency Management Is a Complicated Profession Some of that complexity comes from the onslaught of technology that is washing over emergency managers.
One element of that is our new and improving ability to issue warnings. The last ten years has seen emergency managers have the ability to use computer technology to provide alerts and warnings to wired phones or to people who sign-up in advance of a disaster to get warnings.
With the advent of Commercial Mobile Alert System (CMAS) you will have the ability to use cellular phones to warn people in a specific geographic region. Today that is limited to county boundaries, but I expect the definition of the area to be warned will become more specific in time.
Check out the linked podcast above for information on CMAS and how to become an agency that has access to the system. There are some application hoops to jump through, but you can get in the game today.
Like all new systems there are some limitations, such as: