EXCURSION FROM TXWY DURING A TAXI OP IN A SNOW STORM.

Narrative

TAXI IN WAS TREACHEROUS. BLUE LIGHTS WERE OCCASIONALLY; SPORADICALLY OBSCURED BY SNOW AND BLOWING SNOW AND DEEP SNOW DRIFTS. ARPT SIGNAGE WAS MISSING (PER UNITED STATES STANDARDS) OR OBSCURED; MAKING TAXI IN A SLOW; TEDIOUS PROCESS. AFTER SVCING; THE ACFT WAS PUSHED BACK FROM GATE ONTO N END OF RAMP FACING W FOR DEICING. THE PROCESS WAS SLOW DUE TO WX; AND DURING THAT TIME PLOWING OPS WERE IN PROGRESS ON TXWYS. AFTER ENG START WE WERE CLRED TO TAXI TO RWY 36. WE PROCEEDED OFF THE RAMP TXWY W; L ON TXWY H. INITIALLY THE TXWYS LOOKED BARE ON TXWY W AND TXWY H; BUT ONCE ESTABLISHED ON TXWY H SBOUND; THE PAVEMENT DISAPPEARED CAUSING RELIANCE ON BLUE LIGHTS TO MAINTAIN PATH. (NOTE ALL LIGHTS; WING AND NOSEWHEEL WERE ON AS AIDS AT THIS POINT). SNOW WAS BLOWING AT 20-30 MPH FROM W. WHEN S ON TXWY H; THE INITIAL TAXI CHK WAS RUN AND WE BEGAN LOOKING FOR THE DOGLEG ON TXWY H TO THE SE. I SAW A 'CLR' LINE OF LIGHTS TO THE SE AND PROCEEDED TO KEEP THEM ON MY L. MANY OTHER LIGHTS WERE VISIBLE PAST THIS LINE AND MORE VISIBLE BEFORE IT. JUST THEN THE COPLT NOTED A TAXI LIGHT ON HIS R. IT APPEARED TO BE TOO CLOSE TO THE ACFT. HE SO REMARKED AND I STOPPED. AT THAT POINT THE NOSEWHEEL AND PERHAPS MAIN GEAR HAD LEFT THE PAVEMENT. THE PROB WAS CLR AFTER WE SAT THERE SEVERAL HRS THAT ALL THE LIGHTS ON THE L EDGE OF THE DOGLEG WERE BURIED UNDER SNOW. AS THE PLANE CAME BY AND CLRED THE AREA THEY BEGAN TO SHOW UP; BUT ON TAXI OUT THEY WERE 100 PERCENT OBSCURED AT THAT POINT. SO WHAT APPEARED TO BE THE L SIDE OF THE TXWY WAS REALLY THE R SIDE. IN ESSENCE; I MISSED THE TURN AND HAD CONTINUED STRAIGHT AHEAD OFF THE TXWY. THE REST OF THE STORY WAS SIMPLY SHUT DOWN ENGS AND WAIT FOR BUSSES TO DEPLANE THE PAX. NO INJURIES (VERY SMOOTH TXWY DEPS); NO KNOWN ACFT DAMAGE -- SNOW WAS SOFT. JUST COULDN'T MOVE ANY MORE AFTER STOPPING.