Oregon’s snowpack looks good, but drought conditions persist

Oregon

A hydrologist explains why this much snow doesn't mean Oregon's drought is over

Mt. Hood Meadows December 17, 2021 (KOIN)

PORTLAND, Ore. (KOIN) – The snowpack in basins across Oregon jumped from almost nothing to near or well-above median levels within a matter of a month, according to the Natural Resources Conservation Service, after storms throughout December brought significant snow to the region. 

While this improved snowpack is a welcome sight, scientists say it doesn’t mean the drought is over in Oregon. According to the general outlook NRCS published on Jan. 1, nearly 96% of the state is still in a drought category due to weather conditions the state has experienced over recent years. The report says nearly 52% of the state is still in severe to exceptional drought. 

“Increased snowpack and precipitation will be required to assist in potential drought relief, particularly in the regions in Central and Eastern Oregon impacted by the extreme D3 and exceptional D4 drought,” Scott Oviatt, snow survey supervisory hydrologist for the Natural Resources Conservation Service, wrote in an email to KOIN. 

When the water year began on Oct. 1, snowpack was scarce in Oregon after a summer of above-normal temperatures. That changed in late December when a storm delivered more than 1.5 feet to high elevations in the Cascades. Several parts of Southern Oregon received near-record snow. 

The Oregon snowpack map released by the USDA and NRCS on Jan. 11, 2022 shows the entire state’s snowpack is above median levels. Courtesy USDA/NRCS

Oviatt said major watersheds in Western Oregon and Southern Oregon have received more snow, with respect to the median, than those in Northeast and Eastern Oregon. He said this is an excellent start to building a significant statewide snowpack that could potentially help relieve Oregon’s multi-year drought. 

The report says parts of Oregon also received significant rainfall in fall and early winter. However, Oviatt said rain totals are lower than the snowpack median values right now because of the limited precipitation in October and November. 

Oregon has been impacted by several atmospheric rivers that brought heavy rain to the region in the early winter. Oviatt warns that while this moisture is beneficial in some ways, it can be harmful to the snowpack. 

“Any time there is potential for rain-on-snow, as is often the case during atmospheric river events, there is a threat of a rapid reduction of snowpack due to the warm rain and temperatures melting the snowpack prematurely, and often rapidly,” he said. 

He said the weather through the remainder of winter will determine if the snowpack levels will continue to improve and if they’ll mitigate Oregon’s multi-year drought. To maintain the snowpack and ensure a long, slow spring snowmelt runoff, he said Oregon will need cooler temperatures and more mid-and high-elevation snow accumulation. The lower elevations will also need continued precipitation through late spring. 

He hopes the region will avoid prolonged warm and dry periods or early snowmelt due to high temperatures. He said both those things have occurred in recent years. 

There is some good news on the horizon. The NOAA Climate Prediction Center expects below-average temperatures across Oregon for the next two months and above-average precipitation across the northern part of the state. 

“The forecast of cooler temperatures is a good scenario for building snowpack, however the limited precipitation forecast (especially in southern Oregon) is not necessarily a good signal for the remainder of winter,” Oviatt said. 

He said it will be interesting to see how conditions evolve and how they will impact snowpack accumulation across the state. 

Oregon’s median snowpack level is based on values recorded between 1991 and 2020. 

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