VOLCANO, Hawaii (AP) — Hawaii Volcanoes National Park remained closed for a second day Wednesday as officials waited for a change in wind direction to blow away sulfur dioxide belching from Kilauea volcano.
The National Park Service said air conditions were worse than Tuesday, when 2,000 people were evacuated from the park.
‘‘This morning, with it being cool and some warmer air on top of it, it has kind of created a pancake effect, so we have some more of the vog lower down,’’ said Michael Larson, the park’s incident information officer.
So-called ‘‘vog,’’ or volcanic fog, is formed when sulfur dioxide gas reacts with sunlight, oxygen, dust particles and water in the air. Tiny droplets known as sulfate aerosols are created, along with sulfuric acid and other substances.
Officials were optimistic the southeasterly winds would change to the normal northeasterly trade winds today.
Meanwhile, Big Island residents living in communities outside the park were advised by Hawaii County Civil Defense to remain alert to the possibility of worsening conditions in their areas. The Volcano Charter School remained shuttered Wednesday.
A Red Cross emergency shelter was closed in Hilo after six people spent the night to avoid the sulfur dioxide fumes, civil defense officials said.
The U.S. Geological Survey’s Hawaiian Volcano Observatory said the most recent sulfur dioxide measurement was taken Monday, when 800 metric tons of the gas escaped from Halemaumau Crater atop the volcano. A metric ton is 2,205 pounds.
Sulfur dioxide from the crater had typically measured 150 to 200 metric tons per day before the emission rate began increasing in late December. By mid-March, the observatory recorded the highest emission since measurements began in 1979 — 1,800 to 2,000 metric tons per day.
The park evacuation included the 42-room Volcano House hotel and the Kilauea Military Camp, a vacation destination for military families. The evacuees were taken to hotels in Hilo.
Kilauea, one of the world’s most active volcanoes, began erupting Jan. 3, 1983.