Narrative:

Flying below clouds in valley between 2 hills with tops of hills at 2900-3500 ft MSL. Valley continued low hills with tops of 1500 ft. Heavy downpour began resulting in loss of forward visibility. Called ATC and asked for IFR climb. Controller responded that he did not have good radar coverage in our area, remain VFR. My passenger, a low time pilot, displayed some real concern about lack of visibility and hills. I started a climb away from terrain, circling. I told ATC I needed an IFR climb 'now.' ATC responded immediately (he was also busy with dulles traffic) and had me identify, then gave squawk code. Rest of flight was uneventful. Stay out of valleys on rainy days.

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Original NASA ASRS Text

Title: C172 PLT FLYING IN A VALLEY ENCOUNTERED HVY RAIN AND REDUCED VISIBILITY. HE SUBSEQUENTLY OBTAINED AN IFR CLB CLRNC.

Narrative: FLYING BELOW CLOUDS IN VALLEY BTWN 2 HILLS WITH TOPS OF HILLS AT 2900-3500 FT MSL. VALLEY CONTINUED LOW HILLS WITH TOPS OF 1500 FT. HVY DOWNPOUR BEGAN RESULTING IN LOSS OF FORWARD VISIBILITY. CALLED ATC AND ASKED FOR IFR CLB. CTLR RESPONDED THAT HE DID NOT HAVE GOOD RADAR COVERAGE IN OUR AREA, REMAIN VFR. MY PAX, A LOW TIME PLT, DISPLAYED SOME REAL CONCERN ABOUT LACK OF VISIBILITY AND HILLS. I STARTED A CLB AWAY FROM TERRAIN, CIRCLING. I TOLD ATC I NEEDED AN IFR CLB 'NOW.' ATC RESPONDED IMMEDIATELY (HE WAS ALSO BUSY WITH DULLES TFC) AND HAD ME IDENT, THEN GAVE SQUAWK CODE. REST OF FLT WAS UNEVENTFUL. STAY OUT OF VALLEYS ON RAINY DAYS.

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.