We can thank an El Niño and some associated atmospheric shenanigans for this bounty of water.
“We’re in a weak El Niño,” said NOAA meteorologist Tom Di Liberto. “The warm ocean component of El Niño started in the Fall. But it wasn’t until February that the atmospheric part of El Niño switched on.” El Niño’s tend to bring wet weather to the US West coast. But this year, Di Liberto noted, there were extra complications that were hard to predict. “The polar vortex allowed cold air to drop out of the Arctic, effecting Pacific Northwest temperatures,” Di Liberto said.
What about March? “There’s no clear signal as to whether we will have greater or less than normal precipitation. 40 percent for above, 60 percent below,” Di Liberto said. “But the 30-day March forecast for the northeast corner of Oregon is colder than average. You should probably keep your down jackets handy.”
On Monday, as winter nears its end, the snowpack in the Wallowa Mountains and across the Snake and Imnaha Basins looks great. The Natural Resource Conservation Service (NRCS) SNOTEL site at Aneroid Lake reports a snow water-equivalent of 107 percent of the 30-year average. Snow pack water equivalent at Mt. Howard, totals 108 percent of the 30-year average.
Even better, it’s not just the high elevations that are sequestering the region’s summer water supply. At lower elevations (below 5,000 feet) the snow pack also ranks at 100 percent or higher. And there is still room for improvement. Snow accumulation here usually peaks in mid to late March according to NRCS data. So far, our region has accumulated more snow than in 2017, a year that many in Wallowa County ranked as an “old-fashioned winter.”
“In early February the storm track changed,” said Scott Oviatt, NRCS Oregon Snowpack Survey Supervisor. “The previous storm pattern had been from south to north. But on February 8, it changed and storms with cold Canadian air began coming in from the north. That brought a lot of snow.”
Regionally, snow pack in the Lower Snake, Burnt, Powder, and Imnaha basins is a stunning 127 percent, while the John Day and Malheur basins log in with a mind-boggling 150 and 160 percent of the 30-year average, respectively. In all of Oregon, only the Hood /Lower Deschutes/Sandy River basins are below 100 percent of normal.
There were multiple factors that made the jet stream change it’s position frequently, including the “Madden-Julian Oscillation”—a surge of tropical moisture that can push into temperate regions, and high pressure over the Pacific that came and went. “We had a really convoluted jet stream,” Di Liberto said. “There was really a lot of random, very chaotic behavior of weather going on”
With lots of snow in our mountains and foothills, Oviatt is cautiously bullish about summer water supplies. “We fully expect that our March water outlook for summer stream flow will be a good one,” he said. “If cold temperatures hold, we’ll have good stream flow. But if we have a warm dry spring, that could all change, especially if we lose snowpack at lower elevations.”