Boulder County will commence its annual outdoor emergency siren testing on April 7, 2025, as part of flood season preparedness. Audible tests are scheduled at 10 a.m. and 7 p.m. on the first Monday of each month through August, beginning in multiple communities. After April, only Boulder and Lyons will continue audible testing, while other communities transition to silent tests. These sirens are designed to alert individuals outdoors to emergencies such as severe weather or wildfires. Residents