I was heading home to Kailua from Pearlridge Friday and was trying to figure out if it would be more convenient to stop at Home Depot near Pearl Highlands or go to the Iwilei store.

When I got on Kamehameha Highway, I tried to judge the distance to Pearl Highlands by looking for the nearby high-rises, but these twin buildings that usually stick out like corn silos in Iowa were impossible to see in the vog that had drifted to O’ahu from Kilauea Volcano on the Big Island.

Back on the Windward side, I could barely make out the faintest outline of the Koolaus from Castle Junction. After the rain clouds rolled in and combined with the volcanic haze, it looked like an noxious alien atmosphere out of Star Trek.

This is scary stuff. I lived in Hilo for many years and seldom saw sustained vog this thick from my home less than 30 miles from the vent. I can imagine what it was like on the Big Island over the past week as Kona winds kept the haze over populated areas in Hilo, Puna and Ka’u instead of blowing it out to sea.

The scary thing is that much of the sulfur dioxide and ash is coming from a relatively small fissure in Halema’uma’u Crater at Kilauea’s summit; imagine what we could be facing if a much larger fissure opened.

Geologists have little experience with this kind of explosive activity at Kilauea that has seldom occurred in modern times. They really don’t know what could happen.

The volcanic fumes have already caused short-term evacuations of the national park and nearby subdivisions, and the longer it lasts the more potential for the foul air to affect the public health, agriculture and tourism.

There’s nothing we can do to turn off the volcano, but it would be prudent to make contingency plans to deal with the broad impact.

“We haven’t seen the full range of activity for Kilauea, and it may be uncomfortable, and it may be uncomfortable for quite a while,” said Don Thomas of the Center for the Study of Active Volcanoes at the University of Hawai’i-Hilo.