Story highlights The National Weather Service issues an ashfall advisory

Latest readings say ash plume has risen to 37,000 feet -- nearly double previous height

The Pavlof Volcano, on Alaska's remote Aleutian Island archipelago, last erupted in 2014

(CNN) Alaska's Pavlof Volcano, which erupted unexpectedly over the weekend, continued to rumble and fling ash into the sky Monday, the Alaska Volcano Observatory said.

The ash plume is now 37,000 feet high and trails some 400 miles to the northeast over the Alaskan interior. Aviation alerts were up in the region.

Flying over Volcano eruption in Aleutian Islands A photo posted by Colt Snapp (@coltsnapp) on Mar 27, 2016 at 10:40pm PDT

Citing Kristi Wallace, a geologist with the observatory, CNN affiliate KTVA reported that the main concern is the ash cloud that has been growing since the eruption and obscuring area air traffic.

Bering Air and PenAir canceled at least some flights Monday, according to KTVA.

UPDATE: Flight cancellations across multiple airlines due to Pavlof eruption: https://t.co/bhoWXnWcDA pic.twitter.com/3NIdcNFkoy — KTVA 11 News (@ktva) March 28, 2016

Wallace reportedly said she doesn't expect ash to fall, except for trace amounts in the village of Nelson Lagoon.

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