The Semisopochnoi Volcano in the Aleutian Islands has been especially active in the last few days, prompting the U.S. Geological Survey to upgrade its aviation code to yellow and its alert level to "advisory."

Megan Edge
Matthew Sturm, 62, is preparing for another of his long-distance traverses, versions of which he has executed since 1990, starting in Circle and heading north toward Fort Yukon and beyond. They'll take snow measurements along the way. Ned Rozell
Despite a few dirty particles, Denali air is good stuff. In a 2013 report on air quality in national parks, Denali was the only park in the country with visibility rated "in good condition," while 156 others warranted ''moderate concern" and 189 "significant concern."Ned Rozell
The R/V Sikuliaq, whose name means "young sea ice," will give researchers access into the ice edge, the site of dramatic climate changes. Yereth Rosen
The noisiest places found so far in the world’s oceans are some of the most scenic – saltwater fjords where glaciers drop chunks of blue-white ice, according to newly published data collected in Alaska and Antarctica.Yereth Rosen
Christina Neal, a geologist with the Alaska Volcano Observatory for nearly 25 years, moves to Hawaii to become the Hawaiian Volcano Observatory's new scientist-in-charge.ociated Press
A new device promises to automatically track, and shoot down pesky mosquitoes with a burst of laser energy. It's perhaps the most high-tech way to massacre some mosquitoes.Sean Doogan
State and federal managers are turning to village residents to help plan what promises to be another summer of frustration, with restricted fishing in a region that depends on salmon as a main food source.Lisa Demer
Far northern lakes have formed, filled and emptied for thousands of years, but this is the first time scientists have observed it with instruments. Ned Rozell
Among scores of bird and mammal species, there will be winners and losers as trees and shrubs expand northward and wildlife habitat transforms through the rest of the 21st century. Yereth Rosen