Is energetic decadal variability a stable feature of the central Pacific Coast's winter climate?

The central Pacific Coast of the United States is one of the few regions in North America where precipitation exhibited a high proportion of variance at decadal time scales (10 to 20 years) during the last century. We use a network of tree ring-width records to estimate the behavior of the observed decadal pattern in regional winter precipitation during the last three and a half centuries. The pattern was most vigorous during the mid and late 20th century. Between A.D. 1650 and 1930, proxy estimates show a limited number of events separated by longer intervals of relatively low variance. The multicentennial perspective offered by tree rings indicates the energetic decadal pattern in winter precipitation is a relatively recent feature. Until a physical mechanism can be identified that explains the presence of this decadal rhythm, as well as its inconsistency during the period of record, we cannot rule out the possibility that this behavior may cease as abruptly as it began.