UNITED NEWS INTERNATIONAL (UNI) — Officials placed part of Hawaii’s Big Island under a red aviation alert as volcanic activity increases in the region.

The U.S. Geological Survey issued the alert Tuesday, May 15 after Kilauea volcano sent a plume of ash thousands of feet into the air.

Officials said ash has been spewing from the volcano’s crater almost continuously and drifting miles to the southwest.

The Hawaiian Volcano Observatory said Tuesday, “At any time, activity may become more explosive.”

This means ash plumes could worsen and the volcano could spew chunks of molten rock and lava.

Officials aren’t sure what caused Tuesday’s increased activity but fissures have been oozing lava for nearly two weeks after hundreds of earthquakes rattled the island.

These cracks forced hundreds of residents in and around the Leilani Estates neighborhood to evacuate their homes.

Officials warn residents to be wary of toxic sulfur dioxide issuing from the fissures.