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i j , . fW water equivalent, during relatively warm midday periods. This problem is suspected to be caused by inadequate compensation of the load cell's temperature dependence. Otherwise, the gauge compared very well with a nearby calibrated Belfort weighing gauge. If one ignores the hours when the ETI gauge indicated precipitation but the Belfort did not, the total accumulation by the two gauges was very,similar. The two gauges rarely differed in hourly precipitation amount by more than 0.015 in. ~ t H n l ~ ~ I I Agreement between the two gauges was better than between either gauge and a nearby snowbird. Although the snowboard observations were highly correlated with both gauges, the snowboard received from 6 to 9 pct more snowfall than the gauges over the test period. Part of this difference may have been caused by gauge undercatch, although wind speeds were very limited during snowfall in the protected test clearing. It is speculated that part of the difference may have been caused by downhill drifting of snow onto the snowboard between some storms. The observations indicated that either the ETI or Belfort gauge can provide accurate precipitation measurements when protected from significant wind. The ETI gauge has the advantages of requiring infrequent servicing and providing digital, computer-compatible data without laborious manual chart reading. 8.8. Super, A. B., andA. W. Huggins, 1993: Relationships between storm total supercooled liquid water flux and precipitation on four mountain barriers. J. Weather Modification;25, 82-92. ABSTRACT There is a commonly held view that large winter orographic storms tend to be efficient in converting supercooled liquid water to snowfall while small storms tend to be inefficient and therefore, are more susceptible to cloud seeding. To test this conceptual picture, supercooled liquid water flux and precipitation amounts were compared for 4 different mountain regions in Arizona, Colorado and Utah. Supercooled liquid water flux totals were estimated for entire storm periods from vertically-integrated microwave radiometer measurements and wind speeds within about 1 km of the mountain crest, corresponding to the layer expected to contain most of the supercooled liquid water. Per storm precipitation totals were measured near the radiometer sites. Comparison of storm total supercooled liquid water flux with total precipitation revealed apparent significant relationships between the two variables at all sites. The larger supercooled liquid water flux- producing storms tended to have larger precipitation amounts. When the effect of storm duration was removed, partial correlations coefficients between supercooled liquid water flux and precipitation were significant at 3 of the mountain sites. None of the data sets supported the concept that large precipitation- producing storms are highly efficient in converting supercooled liquid water flux to snowfall. This suggests that large storms are efficient during some phases when abundant snowfall is produced, but inefficient during other phases when supercooled liquid water flux is abundant. This hypothesis was tested for one well-observed storm. Precipitation efficiency was estimated throughout the storm's duration'by comparing snowfall with upwind supercooled liquid water flux plus ice flUx. The prefrontal phase was very inefficient and produced most of the total supercooled liquid water flux. The frontal phase was more efficient and about half the flux of liquid and ice was converted to snowfall. The postfrontal phase had little supercooled liquid water flux but significant ice flux. However, it was inefficient in converting cloud ice to snow on the ground. 47