This info comes from our friends at PacifiCorp Energy:
PacifiCorp Energy intends to test its park evacuation sirens at Beaver Bay and Cougar Campgrounds near Cougar, Washington on Wednesday, January 30th at approximately 11:30 AM. The test should only last a couple of minutes if all is working properly.
Testing is being performed in order to check the operation of the devices should they be needed for an emergency. Residents of the Cougar area were sent notices about this test a few weeks ago and were previously informed that these sirens are only intended for the before-mentioned parks. Additional testing will be required in the future and we will inform you and residents prior to testing.