ANCHORAGE, Alaska (AP) — A remote volcano in Alaska’s Aleutian Islands that has been active in recent weeks spewed an ash cloud up to 30,000 feet (9,144 meters) in the sky on Friday, prompting warnings to pilots.

“Significant ash emissions” were possible for several hours following the unrest on Shishaldin Volcano, according to the Alaska Volcano Observatory.

Volcanic ash is angular and sharp enough for use as an industrial abrasive. The powdered rock can cause a jet engine to shut down.

The volcano is 679 miles (1,093 kilometers) southwest of Anchorage, near the center of Unimak Island, the largest island in the Aleutians.

About 40 people live in False Pass on the island’s east side, and the National Weather Service issued a statement saying trace ashfall was possible around the village.