WHEN EN ROUTE, THE ACFT COLLIDED WITH POWER LINES WHERE THEY CROSSED OVER A HIGHWAY ABOUT 39 FT AGL. TWO WITNESSES NEAR THIS LOCATION REPORTED THAT THE ACFT WAS FLYING LOW & WAS FOLLOWING THE HIGHWAY ON A WESTERLY HEADING WHEN THE ACFT STRUCK THE WIRES. THE WIRE STRIKE OCCURRED AS THE ACFT WAS STARTING TO CROSS A VALLEY ABOUT 8 MI WIDE. SUBSEQUENTLY, THE ACFT CRASHED INTO RISING TERRAIN ON THE OPPOSITE SIDE OF THE VALLEY. WITNESSES IN CARS NEAR THAT AREA STATED THAT THE ACFT WAS FLYING LOW OVER THE HIGHWAY & WAS ZIG-ZAGGING BACK & FORTH. JUST PRIOR TO CRASHING, THEY SAW THE ACFT GO INTO A STEEP BANK, THEN IT DISAPPEARED FROM THEIR VIEW AS IT WENT BEHIND A HILL. AN EXAM OF THE CRASH SITE REVEALED THAT THE ACFT WAS IN NEAR LEVEL FLT WHEN IT HIT TREES ON THE SIDE OF A HILL, THEN IT CRASHED INTO A 9 DEG RISING SLOPE. THE PLT WAS SERIOUSLY INJURED & COULD NOT RECALL THE FLT OR THE ACCIDENT. WITNESSES STATED THAT THE ACCIDENT OCCURRED ON A DARK NIGHT WITH LOW CEILINGS & WITH LIGHT SNOW FALLING.