The woman captured the "eerie" siren sounds along the coast of Waikiki Beach warning Honolulu residents and visitors about the tsunami.

While Monday's tsunami response was ultimately more of a drill than a true emergency, the traffic it triggered offered a real-time test of Oahu’s evacuation capacity — one that state officials admit was deeply strained.

The Pacific Tsunami Warning Center’s latest tsunami warning update for Hawaii says that first waves to hit Kauai measured at amplitude 3 to 4 feet in Hanalei, and 0.7 to 0.8 feet Nawiliwili. Tsunami amplitude is “measured relative to normal sea level,” according to the 8 p.m. update.