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Precipitation totals for the first six month" of the season (October through April) are about 96 percent of normal with the range extending from 56 per- cent near Leadville to 198 percent near Fountain. SlIowpack. Mountain snowpack on May I is abouT 73 percent of average for this time of year and 71 percent of last year on the mainstem of the Arkan- sas. On the tributaries, the snowpack measures 41 percent of average and 40 percent of last year. Rl'senoir storages. which are 100 percent of last year at this time and 126 percent of average. rellect the lower runoff during the latter part of last sea- son and the near nomwl precipilation during the current season. Overall. decreased mountain sno\\'- pack and near average precipilation through April promise slightly below to near nonnal water supplies for the 1992 season. Rio Grande Basin The Rio Grande Basin water supply outlook calls for below average runoff over the majority of the basin in Colo- rado. and average to much above aver- age nmoff in the New Mexico portion of the basin. A relatively wann and dry month. April produced earlier than expected snowmelt. resulting in higher than aver- age runoff and strei.unflow for the month. However. total predicted seasonal run- off has decre<lsed 10 to 30 percent from the April I forecast. Streamflow vol- umes are now expected to be 70 to 85 perce III of average along the mainstcm and tributaries flowing from the San Juan Mountains in Colorado, and 100 ID 105 percent of avefi..lge along the llli.J.in- stem and Rio Chanla in New Mexico. Above to much above average flows, 115 to 180 percent of average. are pre- dicted <.llong tribularil's flowing from the Sangre De Cristos and Jemez moun- tains. 'lnd in the Pecos River Basin. Precipitation was much below aver- age over the majority of the basin, with [Owls ranging from a trace 1O 40 percent of average. Ex.ceptions were located in the vicinity of EI Vado Reservoir, which observed near 150 percent of average. and areas of soulhern New Mexico, which reported 200 to 300 ...ercent of average. Seasonal totals now fi.Hlg~ from 80 percent in the northwest- ern areas of the basin. to near 250 per- cenl of average below Elephant Butte Reservoir in southern New Mexico. Sno'H!pack. A largc portion of the mountain snowpack was depleted dur- ing the month of April. panicularly in New Mexico. The remaining higher elc\'alion snow in the Colorado ponion of the basin is 61 percent of avemgc and I> I percent of last May I. Reservoir storage has increased at most of the major lakes during the month of April as a result of the earlier than nonllal snowmelt runoff. Total storage is now 104 percenl of average ( 114 percent of last May I) in Colorado. and 191 percent of average (118 percent of last year) in New Mexico. Colorado Basin The waler supply forecast for the upper Colorado River Basin calls for near avemge to below average volumes. Forecasts have decreased 5 to 10 per- cent in the upper Colorado mainstcm and San Juan. and decreased 10 to 15 percent in the Green River Basin. April- July streamflow in the uppa Colomdo is expected to range between 20 and 90 percent of the 1961-1990 average. Near record low volumes are expected in many Green River tributaries this spJing. Forecasts are not made for the lower Colorado on May I. Precipitation in the upper Colorado during April was below to well below average. Overall. the upper hasin re- ceived roughly half of the average April precipitation. The driest area Wi1S s~c- tions of eastern Ulah. which received 25 to 40 percent of average. October through April precipitation for the upper Colorado mainstem. S.m Juan. and Green River drainages was 90, 95, and 75 percent of average. respectively. Snowpack. The mountain snowpack in the upper Colorado d~creased sharply during April as a result of much above average lempefiltures. All low and mid- dle elcvation snow had melted as of May I. As of May I. the snow line in the upper C%mdo was at Of ubo\'e 9500 feet. The May I snowpack in the upper Colorado main stem, San J unn. nnd Green River basins was 70. 58, and 35 percent of average, respectively. 2 Streamflow during ^pril was above average in the upper Colorado main- stem and San Juan and below average in the Green River. Lake Powell innow during April was 892.000 acre-feet or 85 percent of average. Because of the above average temper- atures. the spring snowmelt is earlier th.Ul usual this year. Lower elevation basins have already peaked and the mainstem Colorado is expected to peak in late Mayas opposed to the typical mid-June maximum. Reservoir stori.lg~ in the upper Colo- rado Basin was 62 percent of ci..lpacity on April 30. Lake Powell held 13.9 million acre-feel or 56 percent of capac- ity on April 30. Great Basin The water supply outlook for the Great Basin calls for much below average streamtlows. This is the sixth consecu- tive year of below average runoff in the basin, and could potentially he the worst in some areas. Record low slreamtlow volumes are expected in some areas of northem Utah ..md northern Nevada. In southem Ulah. much below average runoff is expected throughout most of the Sevier Basin. Precipitation. The dry pattern affect- ing northern Utah throughout the spring extended into southern Utah during April. Statewide precipitation <lIllOunts ranged from as little as 5 percent of average to nearly 50 percent. In north- ern Utah. April precipitation. averaged about 35 percent while the southem portion of the sl<lte saw only .30 percenl. Seasonal precipitation (October through April) is dose to 70 percent of average in northern Utah and about 100 percenl in southern Ulah. April pr~cipilation in the basins along the east slope of the Sierr<l was only aboul 10 percent of average. The month- ly precipitation in the Humboldt Basin was about 15 percent of average. Sea- sonal precipitation since October I has been about 50 percent of average in the basins along the east slope of the Sierra .md 70 percent of average in the Hum- boldt Basin. Snowpllck conditions throughout the Great Basin remain well below average. Due to the warm, dry weather. snow- packs in Nevada and northern Utah have become virtually non-existent.