LA County is apparently testing their "Beach Emergency Evacuation Lights System" (BEELS) today, Wednesday June 5th
"The Beach Emergency Evacuation Lights System, also known as BEELS, is a new beach evacuation alert system designed for all beachgoers, including those who are deaf or hard of hearing. During a beach evacuation, BEELS will flash white LED lights mounted on permanent structures and some lifeguard towers, as well as broadcast a siren and an audible evacuation alert in both English and Spanish."