Pierce County will test Sumner’s lahar siren system this Tuesday. The sirens will sound off for one minute beginning at 10 a.m., and the city wants to ensure that residents don’t mistake the test as a warning for an impending evacuation, according to the Sumner’s safety page.

No evacuation drill will accompany the test.

Sumner is directly in the path of the expected lahar flow in the event of Mt. Rainier’s volcanic eruption. Lahars—mudflows that can be stirred up by volcanic activity—can be likened to torrents of wet concrete, flowing at freeway speeds, setting as a solid and leaving a trail of destruction in its wake. Geologists estimate Mt. Rainier most recently erupted 500 years ago, and eruptions are estimated every 500 to 1,000 years.

The United States Geological Survey has emergency sirens in Sumner, as well as Orting and Puyallup, operated from a constantly-staffed satellite-monitoring center out of Camp Murray in Lakewood, outside the lahar path.