On October 31, 2020, at 4:28 p.m. AKDT (Sunday November 1 at 12:28 UTC), strong northwest winds near Katmai and the Valley of Ten Thousand Smokes (VTTS) picked up loose volcanic ash.
The dry ash that erupted during the Novarupta-Katmai eruption of 1912 was swept southeast and reached Kodiak Island. However, there were no reports of ashfall in nearby communities near Katmai National Park.
The ash cloud was first reported by an airplane pilot flying at about 20,000 feet (6,096 meters) and was later confirmed by another pilot flying at about 2,000 feet (610 meters).
A Twitter statement from AVO clearly explains that the plume of ash was not related to a new volcanic eruption.
All volcanoes in the Katmai region (Snowy, Griggs, Katmai, Novarupta, Trident, Mageik, Martin) remain in the GREEN color code. Current volcanic alert level: NORMAL.
AVO Katmai GREEN/NORMAL – Resuspended ash due to strong northwesterly winds; no eruption https://t.co/zR9kCTlGzL— Alaska AVO (@alaska_avo) November 1, 2020
This phenomenon is not the result of recent volcanic activity and occurs during periods of high winds and dry snowless conditions in the Katmai region and other young volcanic regions of Alaska.
“We know that what’s getting kicked up isn’t just glacial dust, mineral dust that you can see pretty much everywhere else in Alaska,” Wallace said. “These kinds of dust storms happen everywhere. But when they happen there, we know that the material that’s being picked up is predominantly volcanic ash.”
Resuspended volcanic ash should be considered hazardous and could be harmful to aircraft and health.
1912 Novarupta eruption
On June 6th, 1912, Mount Katmai/Novarupta erupted on the Alaska mainland, just 250 miles (402 kilometers) southwest of Anchorage.
The Novarupta eruption was the most powerful of the 20th century (and 21st so far) and ranks among the largest in recorded history.
The below video combines historic photographs with real accounts of the ashfall by terrified Kodiak residents.
The three-day eruption sent ash as high as 100,000 feet (30,480 meters) above the Katmai region and buried the island of Kodiak in two and a half feet of ash.
The USGS estimates 3.6 cubic miles (15 cubic kilometers) of magma was erupted, about 30 times what spewed from Mount St. Helens in Washington state 40 years ago.