An orchard floor with vigorous winter vegetation will do a better job of capturing winter rainfall and preventing runoff, but also transpires water, reducing stored moisture. Light showers may be prone to evaporation, especially if they are followed by warmer, sunny weather. Wetter soils and those with rolling topography will be more prone to runoff, especially during more intense storms. Of course, not all rainfall is effectively stored in the soil profile, as it depends upon the soil conditions and intensity of the precipitation event. The Shasta station alone posted appreciable rainfall, which was still less than half the January average for that station (Table 3). Still, January was particularly dry, with precipitation totals of less than one-tenth of an inch in five of the six stations. Three of those stations, Shasta (CIMIS #224), Williams (CIMIS #250), and Woodland (CIMIS #226), have recorded 5-year highs (Tables 3,4, and 6). In each of the six Sacramento Valley CIMIS stations listed below, 2021-2022 rainfall levels have surpassed those of the previous two years. With a relatively strong start this fall, rainfall totals for this 2021/2022 water year have exceeded historical average monthly rainfall totals for stations throughout the Sacramento Valley (Tables 1-6, some CIMIS values are flagged for possible inaccuracies). The extent of rainfall in the Sacramento Valley as of late winter Similarly, snowpack totals in the Sierra mountains have dropped below 100% of normal for the first time this water year, although all three regions (Southern, Central, and Northern Sierra) are still at 85-90% of normal for the period. Currently, Shasta Lake is at 36% capacity, Lake Oroville is at 46% capacity and Black Butte Reservoir is at 28% capacity. Not surprisingly, reservoir levels are still low across the region. While the numbers are better than some seasons in the recent past, the comparative lack of rain in January warrants some level of caution. Four months into the water year and season averages are still up from last year in each of the six stations we’re monitoring. Unfortunately, a relatively dry January snapped us all out of dreams of a “normal” year and brought us back to our new (drier) reality. Precipitation patterns brought snow to the mountains and rain to the valleys in amounts not seen for a few years.

The 2021-2022 water year, which began on October 1 st, got off to a promising start. Luke Milliron, UCCE Orchards Advisor, Butte, Tehama & Glenn Counties Curt Pierce, UCCE Irrigation and Water Resources Advisor, Glenn, Tehama, Colusa & Shasta Counties

Precipitation totals sacramento