Weather service warned Karluk and Larsen Bay of wind-blown 1912 volcanic ash

The National Weather Service warned Saturday that strong winds were carrying ash from the 1912 Katmai-Novarupta eruption over western Kodiak Island. Karluk and Larsen Bay were the villages most likely to see haze and possibly trace amounts of ash.

NWS Anchorage said people in sensitive groups or with respiratory ailments should avoid or reduce outdoor activity to avoid inhaling the ash. The special weather statement took effect at 10:42 am Saturday and expired at midnight. Forecasters said the winds should weaken Saturday night.

The ash isn't from a new eruption. Strong northwesterly winds across Shelikof Strait and the waters around western Kodiak Island were stirring up ash left by the 1912 eruption, according to the statement. The U.S. Geological Survey has documented high winds scouring the largely unvegetated deposits in the Valley of Ten Thousand Smokes and carrying ash across the strait to western Kodiak Island. It has also published an image of wind-blown ash carried to Larsen Bay.

The Kodiak Island Borough's hazard mitigation plan describes the 1912 eruption, about 100 miles west of Kodiak, as the largest of the 20th century. It says the eruption released more ash than all other documented Alaska eruptions combined. About a foot of ash fell on Kodiak, the town sat in darkness for 60 hours, and residents suffered sore eyes, temporary blindness and breathing trouble, according to the plan.

USGS guidance on volcanic ash says settled ash can be stirred up by wind for weeks or even years after an eruption. Particles smaller than 10 microns can be inhaled deep into the lungs.

The weather service issued similar ash statements for southwest Kodiak Island on Aug. 29 and Aug. 31. Both named Karluk and Larsen Bay, and the Aug. 31 statement also listed Akhiok. New alerts are posted at weather.gov.