A hot air balloon became VFR in IMC.

Attributes
ACN	242597
Time
Date	199305
Day	Tue
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : apc
State Reference	CA
Altitude	agl bound lower : 1000 agl bound upper : 1800
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Operator	general aviation : personal
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Flight Phase	cruise other
Flight Plan	None
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : commercial
Experience	flight time last 90 days : 50 flight time total : 4400
ASRS Report	242597
Events
Anomaly	inflight encounter : weather inflight encounter : vfr in imc
Independent Detector	other flight crewa
Resolutory Action	flight crew : exited adverse environment
Consequence	Other
Supplementary
Primary Problem	Weather
Air Traffic Incident	Pilot Deviation

Narrative:

At takeoff (approximately XA30 am PDT) skies were clear, wind calm. After about 1/2 hour the skies became light scattered (.2 cover). In order to maneuver my balloon, I climbed to 1800 ft AGL to catch an air current to a favorable, appropriate landing site. While up at 1800 ft, the atmosphere turned IFR due to increased wind flow and associated cooling at 1900 ft. The sky rapidly went from .2 cover to .8 or .9. I immediately descended from 1800 ft to 1000 ft AGL and then to an immediate landing. At all times we could see laterally and vertically but we were close to the ceiling for about 2 mins. As balloons need to maneuver in air currents, we can be encompassed in an IFR situation to which the corrective action is to land immediately. On this day we noted the temperature dew point relationship was close. At flight time some low fog was noted on the eastern side of napa valley but it dissipated as the sun rose and warmed the air. Under clear skies we conducted our flight until the stratus layer formed around XB00 am.

Original NASA ASRS Text

Title: A HOT AIR BALLOON BECAME VFR IN IMC.

Narrative: AT TKOF (APPROX XA30 AM PDT) SKIES WERE CLR, WIND CALM. AFTER ABOUT 1/2 HR THE SKIES BECAME LIGHT SCATTERED (.2 COVER). IN ORDER TO MANEUVER MY BALLOON, I CLBED TO 1800 FT AGL TO CATCH AN AIR CURRENT TO A FAVORABLE, APPROPRIATE LNDG SITE. WHILE UP AT 1800 FT, THE ATMOSPHERE TURNED IFR DUE TO INCREASED WIND FLOW AND ASSOCIATED COOLING AT 1900 FT. THE SKY RAPIDLY WENT FROM .2 COVER TO .8 OR .9. I IMMEDIATELY DSNDED FROM 1800 FT TO 1000 FT AGL AND THEN TO AN IMMEDIATE LNDG. AT ALL TIMES WE COULD SEE LATERALLY AND VERTICALLY BUT WE WERE CLOSE TO THE CEILING FOR ABOUT 2 MINS. AS BALLOONS NEED TO MANEUVER IN AIR CURRENTS, WE CAN BE ENCOMPASSED IN AN IFR SIT TO WHICH THE CORRECTIVE ACTION IS TO LAND IMMEDIATELY. ON THIS DAY WE NOTED THE TEMP DEW POINT RELATIONSHIP WAS CLOSE. AT FLT TIME SOME LOW FOG WAS NOTED ON THE EASTERN SIDE OF NAPA VALLEY BUT IT DISSIPATED AS THE SUN ROSE AND WARMED THE AIR. UNDER CLR SKIES WE CONDUCTED OUR FLT UNTIL THE STRATUS LAYER FORMED AROUND XB00 AM.

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.