Mauna Loa, the world's largest active volcano, is erupting for the first time in nearly 40 years, which has caused an ashfall advisory to be issued for Hawaii's Big Island until 6:00 a.m. local time (11:00 a.m. ET) on Monday (November 28), state officials reported.
The eruption began at around 11:30 p.m. HST on Sunday (November 27) in Moku‘āweoweo, the summit caldera of Mauna Loa, according to the United States Geological Survey, which noted that it was not believed to be threatening to communities located downhill.
The Hawai'i Tourism Authority said it was "closely monitoring" the eruption, also noting that the eruption wasn't believed to threaten nearby communities.
Officials are, however, warning that up to a quarter inch of ashfall may accumulate on parts of the island, with fine ash and volcanic gas possibly being carried down by winds.
“People with respiratory illnesses should remain indoors to avoid inhaling the ash particles and anyone outside should cover their mouth and nose with a mask or cloth,” the National Weather Service in Honolulu said via CNN.
“Possible harm to crops and animals. Minor equipment and infrastructure damage. Reduced visibility. Widespread clean-up may be necessary,” the agency added.
Lava flows are contained in the summit area, which is why the downslope communities aren't believed to be threatened by the eruption, according to the Hawaiian Volcano Observatory.
“Based on past events, the early stages of a Mauna Loa eruption can be very dynamic and the location and advance of lava flows can change rapidly,” the observatory said via CNN, adding, “If the eruption remains in Moku’āweoweo, lava flows will most likely be confined within the caldera walls.
“However, if the eruptive vents migrate outside its walls, lava flows may move rapidly downslope.”
Mauna Loa, which stretches to half of the island of Hawai'i, last erupted in 1984, which is the volcano's longest prolonged quiet period in its history, having previously erupted 33 times since 1843.