Storm Alerts

Special recommendations on CAP for tropical storms

In general, we strongly recommend that the <area> element of a CAP alert represent the geographic area to be notified, not the incident area. In the case of a tropical storm, this means that the <area> should contain polygons or geocodes for the places that you expect to be affected by strong winds, heavy rain, and other threats from the storm. If the storm is still offshore, this means that the <area> of your CAP alert shouldn't be the storm's current location.

Instead, you can provide a separate Crisis Map layer to specify the storm's current location and forecast track. For each current or predicted storm location, helpful data points to specify in the Crisis Map file include the time when the storm will be (or is) at that location, the storm center's latitude and longitude, and an error radius or area of uncertainty. It's a good idea to describe the storm's location and expected path in your CAP alert's <description> element, too, for users who prefer reading a textual description.