Narrative:

On oct/wed/93, while en route from abq's double eagle airport to lgb, I encountered a fast moving storm 65 mi north of phoenix, az. All advisories that I had received prior to entering this area, including en route advisories, said that the storm was still south of phoenix and was not expected in the northern az area until late that afternoon. I began to encounter some high clouds (bases approximately 10000 MSL), 40 mi southeast of flagstaff, az, and still had 20 mi visibility. As I approached prescott, az, the storm rapidly moved in from the southwest and southeast and the visibility dropped to less than 1 mi, essentially boxing me in a valley. I attempted to go northeast to flagstaff, but the ceiling was still dropping and the precipitation increased to a point where I could not climb out of the valley I was flying above. In addition, all radios became inoperative due to the interference of the electrical storm. Given these 2 factors: 1) I was unable to establish radio contact to fly IFR to an alternative route and 2) the mountain obscuration was impossible to navigation with the ceiling dropping to dangerous minimums, I decided that it was in the best interest of safety of my passenger and the flight to land on state route 169, 1/4 mi west of I-17. Had I received more accurate information on such a violent and fast-moving storm, I would have flown north to flagstaff to wait out the storm.

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Original NASA ASRS Text

Title: PLT OF AN SMA SINGLE ENG LAND ACFT MADE A PRECAUTIONARY LNDG ON A STATE HWY AFTER BECOMING TRAPPED BY WX.

Narrative: ON OCT/WED/93, WHILE ENRTE FROM ABQ'S DOUBLE EAGLE ARPT TO LGB, I ENCOUNTERED A FAST MOVING STORM 65 MI N OF PHOENIX, AZ. ALL ADVISORIES THAT I HAD RECEIVED PRIOR TO ENTERING THIS AREA, INCLUDING ENRTE ADVISORIES, SAID THAT THE STORM WAS STILL S OF PHOENIX AND WAS NOT EXPECTED IN THE NORTHERN AZ AREA UNTIL LATE THAT AFTERNOON. I BEGAN TO ENCOUNTER SOME HIGH CLOUDS (BASES APPROX 10000 MSL), 40 MI SE OF FLAGSTAFF, AZ, AND STILL HAD 20 MI VISIBILITY. AS I APCHED PRESCOTT, AZ, THE STORM RAPIDLY MOVED IN FROM THE SW AND SE AND THE VISIBILITY DROPPED TO LESS THAN 1 MI, ESSENTIALLY BOXING ME IN A VALLEY. I ATTEMPTED TO GO NE TO FLAGSTAFF, BUT THE CEILING WAS STILL DROPPING AND THE PRECIPITATION INCREASED TO A POINT WHERE I COULD NOT CLB OUT OF THE VALLEY I WAS FLYING ABOVE. IN ADDITION, ALL RADIOS BECAME INOP DUE TO THE INTERFERENCE OF THE ELECTRICAL STORM. GIVEN THESE 2 FACTORS: 1) I WAS UNABLE TO ESTABLISH RADIO CONTACT TO FLY IFR TO AN ALTERNATIVE RTE AND 2) THE MOUNTAIN OBSCURATION WAS IMPOSSIBLE TO NAV WITH THE CEILING DROPPING TO DANGEROUS MINIMUMS, I DECIDED THAT IT WAS IN THE BEST INTEREST OF SAFETY OF MY PAX AND THE FLT TO LAND ON STATE RTE 169, 1/4 MI W OF I-17. HAD I RECEIVED MORE ACCURATE INFO ON SUCH A VIOLENT AND FAST-MOVING STORM, I WOULD HAVE FLOWN N TO FLAGSTAFF TO WAIT OUT THE STORM.

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.