SEATTLE -- Rare tornado warnings for a storm in Western Washington triggered quite a bit of anxiety when urgent cell phone alerts went out across the Seattle Metro area warning of a potential tornado that was not considered a danger to the city.
The National Weather Service issued two Tornado Warnings for the Kitsap Peninsula just before noon including the towns of Silverdale and Poulsbo after radar indicated rotation in an approaching thunderstorm.
Those towns are approximately 25 miles west of Seattle and the warnings were localized to that area on the Kitsap Peninsula. The warnings were canceled at 12:16 p.m. and there were no reports of tornado sightings or any damage.
But Twitter lit up with hundreds of residents across the Seattle Metro area and some surrounding heavily-populated suburbs showing that their cell phone's Wireless Emergency Alert sounded and displayed the message: "TORNADO WARNING in this area."
It instructed residents to "take shelter now in a basement or interior room on the lowest floor of a sturdy building" and if you were outdoors, in a car or a mobile home to move to the closest substantial shelter and "protect yourself from flying debris."
The National Weather Service office in Seattle Tweeted a plea in the storm's aftermath noting that no tornado warnings were in effect for Seattle and noting the wide geographic reach of the alert.
"We are getting reports of phones going off outside the warning area," they tweeted. They asked for residents who received the alert to tweet them their location and cell carrier.
They received hundreds of responses in just a few minutes after the post with reports of receiving the alerts coming across multiple cell phone carriers and across much of the Seattle area.
A joint statement released later Tuesday by the National Weather Service and the Kitsap County Department of Emergency Management said that two Tornado Warnings issued by NWS Seattle triggered two Wireless Emergency Alerts "with some overshoot in the area receiving the message." A third emergency alert issued by the Kitsap County Dept. of Emergency Management to shelter in place during the storm resulted in an even broader overshoot of the warned area.
"WEAs may be received outside the targeted alert area (in this case, outside Kitsap County) because WEAs are broadcast from (cell) towers in and around the targeted alert area," the statement read. "This strategy maximizes delivery to mobile phones in the targeted alert area, but can cause overshoot where the WEA message is received outside the alert area."
The statement says newer cell phones have enhanced geotargeting that helps eliminate the overshoot and that approximately 33% of active smartphones today support this new feature.
"The WEA system is an essential part of America's emergency preparedness and has saved lives in weather emergencies where people took action after receiving an emergency alert," the statement concluded.
Tornado Warnings are exceedingly rare in the Seattle area. Just nine have been issued in all of Western Washington since 2009 and the last one was 232 days earlier.