What happened
The pilot of an air-taxi operation initiated a takeoff attempt from a private runway composed of dirt. The surface conditions varied across the width of the strip; while the center section was dry, the edges were muddy and soft. During the acceleration phase of the takeoff roll, the left main landing gear tire encountered the soft, muddy area near the edge of the runway.
This contact caused the tire to turn abruptly toward the left side of the runway. As the aircraft continued its uncontrolled lateral movement, the left gear assembly collided with a large snow bank situated along the runway's edge. The impact with the snow bank arrested the forward motion of the airplane, bringing it to a stop without further incident.
The investigation
The factual narrative indicates that the primary mechanical event was the deflection of the left main landing gear due to surface traction loss on the muddy section of the dirt runway. No other mechanical failures were reported during the roll.