Cellphone alerts startled Southern Californians for the second time this month on Thursday.
This time, it came in the form of an "Emergency Alert" issued by the National Weather Service and was connected to a dust storm warning.
The warning is in effect until 8 p.m. and includes much of far southwest Arizona and southeast California, according to NWS. It applies to eastern Riverside County, but residents in the western portion of the county reported getting the warning, as well.
The first alert came about 5:39 p.m. telling recipients the warning will last until 7 p.m. An updated second alert came at 6:50 p.m. with the news that the warning had been extended an hour.
Messages to the National Weather Service to learn more about Thursday's alerts were not immediately returned.
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NBC4 was contacted by several viewers who were concerned or confused about the alerts.
Residents in Moreno Valley, Eastvale and Riverside told NBC4 they received messages on their cellphones alerting them to the dust storm warning, and advising them to avoid travel.
Andrew S. said the alert was accompanied by the same special ring and vibration that was used to alert Californians to a statewide Amber Alert earlier this month.
On Aug. 5, phones across the Golden State buzzed, beeped and whirred as California sent its first statewide Amber Alert to mobile devices.
The alerts -- dubbed Wireless Emergency Alerts -- were delivered with a special tone and vibration meant to help people with hearing or vision disabilities get the warning.
NBC4 viewers said Thursday evening's dust storm warning came with that same tone.
It was not immediately clear if the latest messages are connected to the Wireless Emergency Alert program, which was created by the Federal Communications Commission (FCC) and Federal Emergency Management Agency (FEMA), and executed by wireless carriers on a voluntary basis.
Refresh this page for updates.
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Photo Credit: Andrew S (@air92503) via Twitter