EMS FLC CLRED TO CROSS 2 RWYS AND HOLD AT THIRD. SNOW CONDITIONS; TWR UNABLE TO GIVE PROGRESSIVE. CROSSED 3 RWYS.

Narrative

IN THIS SITUATION; I; THE COPLT; WAS NOT FLYING. AFTER THE CAPT LANDED ON RWY 35R AT DENVER STAPLETON ARPT; WE WERE INSTRUCTED TO TAXI ON Z TAXIWAY TO D3; CROSS RWY 25; 26R; AND HOLD SHORT OF 26L ON C TAXIWAY. WE WERE ALSO ASKED TO RPT THE FIRE STATION. THE CTLR ADVISED WE WERE NOT IN SIGHT DUE TO FALLING SNOW. THE TAXIWAYS AND RWYS WERE SNOW COVERED AND NOT PLOWED. IT WAS DIFFICULT TO IDENT RWYS AND TAXIWAYS. THE VISIBILITY APPEARED LOWER DURING TAXI THAN THE RPTED RVR OF 5000 FT. OUR LAST KNOWN POS WAS WHEN WE RPTED THE FIRE STATION. (SEE DIAGRAM ON REVERSE SIDE.) DUE TO POOR VISIBILITY; UNFAMILIARITY OF THE ARPT; AND THE INABILITY OF GND CTL TO GIVE US PROGRESSIVE TAXIING; THE CAPT AND I DECIDED TO COUNT THE NUMBER OF RWYS WE CROSS; AND MAKE SURE WE ONLY CROSS 2 RWYS. WE DECIDED THAT THIS METHOD WAS THE BEST WAY TO TAXI BECAUSE THE RWY AND TAXIWAY SIGNS WERE DIFFICULT TO SEE AND INTERPRET. BOTH OF US WERE SO CAUGHT UP IN COUNTING THE NUMBER OF RWYS WE HAD CROSSED; I IGNORED THE RWY IDENTIFIER SIGNS. WE ALSO DIDN'T REALIZE THAT ONE OF THE RWYS WAS SMALL; AND POSSIBLY UNLIT. NEITHER OF US SAW RWY 25 WHEN WE CROSSED IT. WE THEN COUNTED XING 2 RWYS AND TURNED ONTO WHAT WE THOUGHT WAS C TAXIWAY. WE IN FACT CROSSED 3 RWYS; AND TURNED ONTO B TAXIWAY. WE NEVER SAW THAT RELATIVELY SMALL RWY 25; AND SUBSEQUENTLY CROSSED 3 RWYS INSTEAD OF 2. I FEEL THIS SITUATION COULD BE PREVENTED IN THE FUTURE IF A PLT RELIES PRIMARILY ON RWY AND TAXIWAY SIGNS TO AFFIRM HIS POS INSTEAD OF RELYING ON COUNTING RWYS AND INTXNS HE THINKS HE CROSSED. IF ONE MISCOUNTS FOR SOME REASON; THE SAME SITUATION WE HAD COULD OCCUR.