Updated

Trace amounts of ash and the smell of sulfur reached an Alaska city after the latest eruption of a volcano in the Aleutian Islands.

Bogoslof (BOH-gohs-lawf) Volcano erupted late Monday night. The ash cloud reached 25,000 feet high and the Alaska Volcano Observatory raised the aviation code to the highest warning level.

Traces of ash reached the city of Unalaska (un-ah-LAH-ska) about 61 miles southeast of the volcano. Ash in larger amounts can be a health risk and can damage equipment.

The observatory says the volcano was quieting down Tuesday. By 7:30 a.m., strong explosive activity had subsided or ended and the observatory was not detecting infrasound signals or lightning related to strong ash emissions.

Bogoslof has erupted more than 25 times since mid-December.