Narrative:

We had arrived at pdx airport for flight. Existing WX was 5 overcast 1/2 mi visibility and snow, temperature 28 degrees F. There was 3-4 inches of snow on the ground. Runway 10R was closed and snow removal was in progress. Runway 10L was not closed, but had 2 1/2 inches of wet snow and was not being used. 1 hour passed before runway 10R was open and we had been deiced and ready for taxi. WX was now reported as woxof. Moderate snow was falling, temperature was 28 degrees F and the wind was 080 degrees 10 KTS. Our deice had taken 16 mins and it was a total of 25 mins before we were at the departure end of runway 10R. My first officer did a contamination check and we determined we had to return to our gate for additional deicing. (We had asked pdx ground control if we could be deiced at our present position, but were told no.) we had switched to pdx tower for taxi onto runway 10R. Tower had reported 2 1/2 inches of snow on the departure end of runway 10R, visibility was now minus 700 ft estimated and moderate snow was falling increasing to heavy snow fall. Pdx tower cleared as (air carrier) onto runway 10R to taxi east to taxiway B2 and to exit at taxiway B2. We were told that there was an aircraft on approach at 10 mi. Snow depth on the field now was 8-9 inches estimated and the taxi and runway lights were covered by snow. We missed taxiway B2 because we couldn't see it. Pdx tower told us they had us east of taxiway B2 on their ground radar and we confirmed that we had missed the exit. Pdx tower then cleared us to continue to the intersection of runway 10R and runway 3/21, to turn left on runway 3 and to turn right on taxiway M to the ramp. WX conditions now were a 'whiteout.' we could still see tracks on runway 10R, but everything else was untracked snow. Everything looked the same. Pdx tower was helping us with their ground radar and progressive taxi instructions, to help us locate runway 3. We passed the runway signs for runway 3/21, which were above the snow, and with pdx tower's help and their ground radar, thought we had reached a point where we could turn left and be on runway 3. Both myself and my first officer, based on what we could see, felt it was okay to make the left turn onto runway 3. Traffic was now reported to be at 4 mi. I made the left turn and initially everything seemed normal. But then the nose gear left the hard surface. We had not gone far enough to actually be on runway 3. There were no passenger injuries. There was no damage done to the aircraft.

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Original NASA ASRS Text

Title: MLG BECAME STRANDED OFF THE EDGE OF A RWY WHEN THE CAPT FAILED TO TURN AS DIRECTED BY THE TWR DUE TO MODERATE SNOW COVERING UP RWY TXWY SIGNS AND MARKINGS.

Narrative: WE HAD ARRIVED AT PDX ARPT FOR FLT. EXISTING WX WAS 5 OVCST 1/2 MI VISIBILITY AND SNOW, TEMP 28 DEGS F. THERE WAS 3-4 INCHES OF SNOW ON THE GND. RWY 10R WAS CLOSED AND SNOW REMOVAL WAS IN PROGRESS. RWY 10L WAS NOT CLOSED, BUT HAD 2 1/2 INCHES OF WET SNOW AND WAS NOT BEING USED. 1 HR PASSED BEFORE RWY 10R WAS OPEN AND WE HAD BEEN DEICED AND READY FOR TAXI. WX WAS NOW RPTED AS WOXOF. MODERATE SNOW WAS FALLING, TEMP WAS 28 DEGS F AND THE WIND WAS 080 DEGS 10 KTS. OUR DEICE HAD TAKEN 16 MINS AND IT WAS A TOTAL OF 25 MINS BEFORE WE WERE AT THE DEP END OF RWY 10R. MY FO DID A CONTAMINATION CHK AND WE DETERMINED WE HAD TO RETURN TO OUR GATE FOR ADDITIONAL DEICING. (WE HAD ASKED PDX GND CTL IF WE COULD BE DEICED AT OUR PRESENT POS, BUT WERE TOLD NO.) WE HAD SWITCHED TO PDX TWR FOR TAXI ONTO RWY 10R. TWR HAD RPTED 2 1/2 INCHES OF SNOW ON THE DEP END OF RWY 10R, VISIBILITY WAS NOW MINUS 700 FT ESTIMATED AND MODERATE SNOW WAS FALLING INCREASING TO HVY SNOW FALL. PDX TWR CLRED AS (ACR) ONTO RWY 10R TO TAXI E TO TXWY B2 AND TO EXIT AT TXWY B2. WE WERE TOLD THAT THERE WAS AN ACFT ON APCH AT 10 MI. SNOW DEPTH ON THE FIELD NOW WAS 8-9 INCHES ESTIMATED AND THE TAXI AND RWY LIGHTS WERE COVERED BY SNOW. WE MISSED TXWY B2 BECAUSE WE COULDN'T SEE IT. PDX TWR TOLD US THEY HAD US E OF TXWY B2 ON THEIR GND RADAR AND WE CONFIRMED THAT WE HAD MISSED THE EXIT. PDX TWR THEN CLRED US TO CONTINUE TO THE INTXN OF RWY 10R AND RWY 3/21, TO TURN L ON RWY 3 AND TO TURN R ON TXWY M TO THE RAMP. WX CONDITIONS NOW WERE A 'WHITEOUT.' WE COULD STILL SEE TRACKS ON RWY 10R, BUT EVERYTHING ELSE WAS UNTRACKED SNOW. EVERYTHING LOOKED THE SAME. PDX TWR WAS HELPING US WITH THEIR GND RADAR AND PROGRESSIVE TAXI INSTRUCTIONS, TO HELP US LOCATE RWY 3. WE PASSED THE RWY SIGNS FOR RWY 3/21, WHICH WERE ABOVE THE SNOW, AND WITH PDX TWR'S HELP AND THEIR GND RADAR, THOUGHT WE HAD REACHED A POINT WHERE WE COULD TURN L AND BE ON RWY 3. BOTH MYSELF AND MY FO, BASED ON WHAT WE COULD SEE, FELT IT WAS OKAY TO MAKE THE L TURN ONTO RWY 3. TFC WAS NOW RPTED TO BE AT 4 MI. I MADE THE L TURN AND INITIALLY EVERYTHING SEEMED NORMAL. BUT THEN THE NOSE GEAR LEFT THE HARD SURFACE. WE HAD NOT GONE FAR ENOUGH TO ACTUALLY BE ON RWY 3. THERE WERE NO PAX INJURIES. THERE WAS NO DAMAGE DONE TO THE ACFT.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.