Mauna Loa Volcano Is Erupting In Hawaii. Here Are The Dangers To Watch For

The largest active volcano in the world began erupting overnight on Hawaii’s big island where massive Mauna Loa had already been restless for months. As of midday Monday in the Pacific, a number of island residents were sharing images of an eerie red glow in the sky, although lava from the eruption remains contained to the summit area.

Still, the volcano’s history teaches that conditions can shift very quickly and flowing lava is far from the only concern for weary islanders and visitors to keep in mind. Here’s a quick run down:

Lava on the Run

There is currently no immediate threat to people or property from lava, but in the past flows have covered several miles in a matter of just a few hours, running downhill to reach the ocean and destroying every thing in its path.

The areas at highest risk from coming in contact with the molten rock are in a corridor along the southwest corner of the island and also to the east of the summit above the college town of Hilo.

There is also the risk that the magma underground could migrate from being primarily centered in the main caldera area at the summit and move into rift zones downhill. This could lead to eruptions from other locations that are harder to predict. Such an eruption was seen in 2018 of the adjacent Kilauea volcano on the island, leading to the destruction of a number of homes. As of Monday, the USGS reports no apparent movement of magma into rift zones.

Ashfall and Pele’s Hair

Perhaps the most immediate and ubiquitous impact from the ongoing eruption is ash drifting down on to nearby communities. The National Weather Service office in Honolulu issued an ashfall advisory for the entire island Monday morning, calling for as much as a quarter-inch of ashfall to make it to the ground.

The USGS has also warned that fine ash, which is particularly dangerous to respiratory systems and some equipment, may be floating around along with something called Pele’s Hair. This material is essentially thin strands of volcanic glass that are from chemical reactions with gases during the eruption in the caldera. Pele is the Hawaiian goddess associated with volcanoes. It’s not difficult to imagine the dangers from tiny bits of glass floating around and accumulating on the ground. You don’t want this stuff coming in contact with your skin, eyes or lungs in particular.

Vog is No Joke

In additions to lava, ash and glass, eruptions also release plenty of nasty volcanic gases, sometimes referred to as volcanic smog or “vog.” Vog can contain sulfor dioxide and acidic particles that create a visible haze often associated with the phenomenon.

According to the USGS, vog can have negative health impacts, damage crops and create acid rain.

It’s still very early in the eruptive phase, which is actually long overdue for Mauna Loa. The volcano has erupted more than 30 times in the past two centuries, but the last time was nearly forty years ago, in 1984.

Keep an eye on the USGS eruption page for the latest updates and the local civil defense page for emergency preparedness info.