August 8

Canadian Weather Alerts Now Available

Weather plays a critical role in our lives and economy. To help inform on upcoming weather events, the National Weather Service (NWS) issues warnings, watches, and advisories. These alerts are available via the AerisWeather API using the advisories endpoint and within the AerisWeather Mapping Platform (AMP) utilizing the alerts layers.

In Canada, Environment Canada (EC) issues similar alerts, and today we are announcing that Canadian weather alerts are now available within the AerisWeather API and AMP.  Best of all, Canadian alerts are available to all API and AMP users with no additional development required!

Canadian Weather Alerts in the AerisWeather API

For the AerisWeather API, Canadian alerts have been added to the advisories endpoint. Canadian locations can also be used to query the advisories endpoint to return active alerts for that locale. For example, the following would return active alerts for Toronto, Ontario:

Note that as with US alerts, the API will return a no data warning if there are no active alerts.

Canadian postal codes can be used as well:

Latitude and longitude coordinates can also be used to query alerts. For instance, to return alerts for Toronto, Ontario using the latitude/longitude of the city center:

Searching / Filtering Canadian Alerts

Just like querying US alerts, you can query Canadian weather alerts using the search action. For example, the following will return up to 100 severe thunderstorm warnings for both the US and Canada:

But to limit to Canada only, you would append   to the query parameter:

Alternatively, you can use the new Canada filter:

Likewise, to limit results to US alerts you can use either   or .

Canadian Location Codes

Environment Canada issues alerts based on Canadian Location Codes (CLCs) which are similar to the weather zones that the NWS uses within the US for alerts and forecasts. A CLC is a 6 digit number and are prefixed with   within the AerisWeather API, such as   for Toronto.

You can query the AerisWeather API using CLCs as a place, such as providing the above Toronto CLC to the advisories endpoint:

You can also query the places endpoint to obtain the location information for the CLC:

CLCs will also work with other endpoints, such as observations and forecasts. However, similar to US weather zones, passing CLCs to these endpoints will result in the CLC’s centroid being utilized to obtain the observation and forecast data.

Canadian Alerts within AMP

Canadian alerts have been added to the standard alerts layers within AMP and will appear automatically if you are already using the alerts map layer:

US and Canadian Weather Alerts

US and Canadian Weather Alerts

Canadian alerts also work with the various alerts layer modifiers. To display severe weather alerts only, use the  layer:

US and Canadian Severe Alerts

US and Canadian Severe Alerts

For alert outlines only, use :

US and Canadian Weather Alerts as Outlines

US and Canadian Weather Alerts as Outlines

Displaying only the US alerts
In some instances, you may only need to display US alerts on a map. In this case, add the clip-us mask to your map request after the respective alerts layer:

US Only Alerts

US Only Alerts

Displaying only Canadian Alerts
Currently, AMP does not include a  which is on our roadmap. A workaround is to use a combination of the US land mask and the AMP blend function to obtain the wanted results —  :

Canadian Only Alerts

Canadian Only Alerts

Types of Canadian Weather Alerts

Within the US, the NWS supports over 100 alert types, and Environment Canada currently issues alerts for a subset of these, some of which are unique to Canada. Review the EC public alerting criteria for information and criteria on when an alert is issued. Also be sure to review the advisory type documentation for a list of the supported US & Canadian alerts with their codes and colors.

Access Canadian Alerts Today

Start using the Canadian alerts today with your AerisWeather API and AMP subscriptions! Not currently using our services? Start with our free developer trial!


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  1. August 9, 2017 at 7:26 am

    […] have released version 1.7.3 of the Aeris Weather API to production that builds upon the recent Canadian weather alert additions and improved advisory support. We will highlight a few of these changes, though for the […]

  2. August 10, 2017 at 8:13 am

    […] also continue to improve upon existing layers, including the recent addition of Canadian alerts, as well as releasing new layer offerings, such as lightning strikes. Most recently, we’ve […]

  3. January 17, 2018 at 2:37 pm

    […] more in our Developer Team’s blog about alerts. Check out our documetation for alerts in the API or Aeris Mapping Platform (AMP). If […]

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