What happened
The pilot of an air taxi departed from St. Mary's Airport with one passenger on board. While flying at approximately 600 feet AGL along the south bank of the Yukon River, the pilot received a report of aircraft traveling in the opposite direction, also inbound to St. Mary's and positioned along the south bank.
To maintain separation from this traffic, the pilot decided to transition to the north bank of the river. During this maneuver, weather conditions began to deteriorate rapidly. The pilot reported that forward visibility decreased significantly, leading to the onset of whiteout conditions. In an attempt to maintain visual contact with trees and the shoreline, the pilot inadvertently allowed the aircraft to descend until it impacted snow-covered terrain.