17/09/2025
https://www.facebook.com/share/p/19fLuMJQPZ/
There are quite a few stories in the news today about portions of British Columbia waking up to a dusting of ash. While there is ash in the air in this area of Canada, it is not from Mount St. Helens. The forest fire ash that is on cars and homes is from forest fires on the Olympic Peninsula.
How can you tell? There are several ways we can tell this is forest fire ash and not volcanic ash.
1 – The Washington Volcanic Ash Advisory Center was tracking the wind-blown volcanic ash from Mount St. Helens yesterday and the dust cloud of resuspended volcanic ash was only about 10,000 feet high and extended about 15 miles. So, we know that wind-blown volcanic ash did not make it as far north as the reported ash over 160 miles (260 km).
2 – Using the publicly available GOES satellite data, GOES-West PNW sector satellite loop from the National Weather Service, it shows a strong smoke plume going north into British Columbia from the Bear Gulch fire on the Olympic Peninsula, which burned more aggressively in yesterday’s strong winds. https://ow.ly/kSCz50WYjzB
3 – There are noticeable differences between forest fire ash and volcanic ash. Forest fire ash is often black in color, with other colors mixed in like grays and browns. This ash can be various shapes, including thin lines (burned evergreen needles) and leaf fragments. Forest fire ash, like campfire or fireplace ash, is carbon-based and water soluble. It will crumble in your fingers and dissolve in water. However, volcanic ash is very fine rock fragments and does not dissolve in water. It’s more like extremely fine sand with the consistency of flour or baby powder. Ash from Mount St. Helens is usually a uniform pale gray.
Based on satellite data, resuspended ash tracking and photos of the ash on cars today in British Columbia, it is clear that this is wildfire ash. But, this is a good reminder to read up on volcanic ash preparedness so when the next large eruption occurs, communities are ready.
Links:
https://ow.ly/rAJ150WYjzC
https://ow.ly/59C550WYjzF
