Why did people outside of Kitsap County receive a tornado alert Tuesday?
Nov 10, 2021, 11:06 AM
A tornado warning was issued for Kitsap County on Nov. 9, 2021, as part of a storm that also brought hail to the area. (Photo courtesy of KIRO Radio listener Keith)
(Photo courtesy of KIRO Radio listener Keith)
The National Weather Service has released an explanation as to why some people not living in Kitsap County received an emergency tornado alert on Tuesday.
The NWS says conditions were ripe for the formation of a tornado in the Bainbridge Island and central Kitsap areas around noon Tuesday. But officials say many that weren’t in the affected areas also got the emergency alerts to shelter in place, and it’s because of the location of the cell towers.
A statement from the NWS and the Kitsap County Department of Emergency Management says weather alerts are broadcast from towers in and around targeted areas. That maximizes delivery to mobile phones, but can cause an overshoot to other areas not impacted.
About a third of newer cell phones have upgraded technology to eliminate the overshoot issue.
The full statement from the NWS and Kitsap County Department of Emergency Management on the wireless emergency alert activation on Nov. 21 is below:
Today the National Weather Service (NWS) forecast office in Seattle issued two Tornado Warnings for portions of Kitsap County, Washington. The two warnings triggered two Wireless Emergency Alerts (WEA) on mobile devices with some overshoot in the area receiving the message. In addition, the Kitsap County Department of Emergency Management issued a shelter in place warning through the WEA system countywide resulting in a broader overshoot.
WEAs may be received outside the targeted alert area (in this case, outside Kitsap County) because WEAs are broadcast from towers in and around the targeted alert area. 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. Newer cell phones are hitting the market that help to eliminate this overshoot. According to the wireless industry, one-third of active smartphones already support enhanced geotargeting.
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.
