How to predict Vog for the Big Island

During a volcanic eruption, the vog on the Big Island is primarily determined by the direction of the wind. If you can visualize the overall wind patterns for the island, you can see the wind passing over the volcanic emission and where it will go on the island. A tool which allows you to see future wind patterns, will allow you to predict the vog in your area. There is such a tool on the web called Windy.com.

The wind typically blow from the east. When it hits the Big Island eastern point, the wind splits into a northern stream and a southern stream. The southern steam will pass over the volcanic eruptions and typically carry the emission out to sea, while the northern stream stays clean. Both streams may wrap back toward the west coast once they get around the island. The vog at any point along the west coast will be determined by which stream dominates at a certain time and place.

Waikoloa is on the northern part of the west coast will typically get the good air from the northern stream. But changing wind patterns may allow the vog from the southern stream to reach Waikoloa. When there is vog at Waikoloa, it will be just in the Yellow range, even if the vog further south is in the Orange or Red range.