alert

To define basic information about a current event, use the <alert> entity.

If an event occupies more than one ongoing location at the same time, it's better to split the event into multiple alert objects. For example, if a forest fire spans multiple states, you can break up the alerts into multiple alerts, one for each state. That way, you provide specific emergency information to each state, and you update the fire situation more accurately.

If an event changes rapidly, like a hurricane that moves from east to west, then we recommend that you make periodic updates to the alert. Don't remove the existing alert from your feed. Instead, issue a new alert that refers to the previous alert.

Attributes

Table 1 describes the attribute value for the <alert> entity:

Table 1. <alert> entity attribute

Element name Optionality Type Description

Element name	Optionality	Type	Description
`xmlns:cap`	REQUIRED	`string`	The `xmlns` attribute must reference the CAP URN as the namespace. Example: `<cap:alert xmlns:cap="urn:oasis:names:tc:emergency:cap:1.2"/>`

xmlns:cap

REQUIRED

string

The xmlns attribute must reference the CAP URN as the namespace.

Example:

<cap:alert xmlns:cap="urn:oasis:names:tc:emergency:cap:1.2"/>

Elements

Table 2 describes the sub-element values for the <alert> entity:

Table 2. <alert> entity elements

Element name	Optionality	Type	CAP and Google notes and requirements
`<identifier>`	REQUIRED	`string`	Provide the ID of the alert that represents the event. The value of the `<identifier>` element must be unique across all events.
`<sender>`	REQUIRED	`string`	The `<sender>` element identifies the originator of the alert. It can't include spaces, commas, or restricted characters.
`<sent>`	REQUIRED	`dateTime`	If the location cited in the `<area>` block falls within a single time zone, use the `<sent>` element to specify time in that zone. When applicable, include an allowance for Daylight Savings time. When the content of a message applies across multiple time zones, use UTC times in preference to local times.
`<status>`	REQUIRED	`AlertStatus`	Google only publishes publicly available alerts that have a `<status>` element value of `Actual`. Caution: Google might suspend publishers who send test messages as `<status>` `Actual`.
`<msgType>`	REQUIRED	`AlertMsgType`	An `UPDATE` or `CANCEL` `<msgType>` must include at least one `<references>` element. The CAP standard specifies the following: Any alert message that updates a previous alert uses UPDATE and sets `<references>` element values to all previous messages that haven't reached their `<expires>` date. The `UPDATE` or `CANCEL` `<msgType>` element must apply to a non-expired alert. Therefore, all related messages and unexpired alerts must be referenced when an `UPDATE` or `CANCEL` `<msgType>` is issued. For more information, see Event changes or expiration.
`<source>`	OPTIONAL	`string`	The `<source>` element denotes the particular source of the alert. An example is an operator or a specific device.
`<scope>`	REQUIRED	`AlertScope`	The `<scope>` element denotes the intended distribution of the alert message. Note: Google only publishes alerts with a `Public` `<scope>` value.
`<restriction>`	CONDITIONAL	`string`	If the `<scope>` element value is `Restricted`, then the `<restriction>` element is required. This element describes the rule to limit the distribution of the restricted alert message.
`<addresses>`	CONDITIONAL	`string`	If the `<scope>` element value is `Private`, then the `<addresses>` element is required. This element lists the intended recipient of the alert message. You can include multiple space-delimited addresses, but you must enclose addresses that include whitespace in double quotes.
`<code>`	OPTIONAL	`string`	The `<code>` element denotes special handling of the alert message. Note: Usually, Google doesn't support the `<code>` element.
`<note>`	CONDITIONAL	`string`	If the alert contains either of the following element values, then the `<note>` element is required: `<status>Exercise></status>` `<msgType>Error></msgType>`
`<references>`	CONDITIONAL	`string`	If the `<msgType>` element value is either `UPDATE` or `CANCEL`, then the `<references>` element is required. When your system republishes CAP content from another publisher, include the full CAP alert. To link edited content to the original source, use the `<references>` tag. If you reference multiple messages, then use whitespace as a delimiter.
`<incidents>`	OPTIONAL	`string`	The `<incidents>` element collates multiple messages that refer to different aspects of the same incident.
`<info>`	REQUIRED*	`info`	At least one `<info>` element must be present. Multiple `<info>` blocks must all have the same `<category>` and `<event>` element values.

* Google requires elements that have a bold and red REQUIRED optionality, but those elements are optional in the CAP standard.

Example

<alert xmlns="urn:oasis:names:tc:emergency:cap:1.1">
    <identifier>AL20110412020900TornadoWarning</identifier>
    <sender>w-nws.webmaster@noaa.gov</sender>
    <sent>2011-04-11T21:18:07-05:00</sent>
    <status>Actual</status>
    <msgType>Alert</msgType>
    <scope>Public</scope>
    <info>
        <language>en-US</language>
        <category>Met</category>
        <event>Tornado Warning</event>
        <urgency>Immediate</urgency>
        <severity>Extreme</severity>
        <certainty>Observed</certainty>
        <effective>2011-04-11T21:09:00-05:00</effective>
        <expires>2011-04-11T21:30:00-05:00</expires>
        <headline>Tornado Warning issued April 11 at
        9:30PM CDT by NWS Birmingham</headline>
        <description>Tornado is observed near Cleburne.</description>
        <instruction>
          Don't wait to see or hear the tornado.
          For your protection, move to an interior room on the lowest floor
          of your home or business.</instruction>
        <area>
            <areaDesc>Cleburne</areaDesc>
            <polygon>33.61,-85.58 33.65,-85.58 33.72,-85.58
            33.81,-85.36 33.7,-85.34 33.7,-85.33 33.68,-85.33
            33.61,-85.58</polygon>
        </area>
    </info>
</alert>