PORTLAND, Ore. (KOIN) – Whether you’re waiting patiently or anxiously, I think we all can agree on the need for more snow up on the mountains.
November is the early window of the snow season. We have time to crank the temperatures down and to invite plenty of snow in. Yet, coming off such a nasty drought, it would feel better if the snow water equivalent wasn’t so poor across the western United States right now. This includes all of Oregon and most of Washington.
If we look at the snow water equivalent graphic below, updated November 29, 2021, Oregon could use a jolt of life. Each basin is underperforming and we are the only state that is completely in red. It’s hard to believe because November has brought in multiple rain events, bringing our rain total above average for the month.
What’s the deal? The chain of atmospheric rivers that have swept across the Pacific Northwest (PNW) have brought in moisture, but also warm air. That warm air has boosted the snow levels and we haven’t had the results that we would want for late November. It’s not for a lack of trying! It’s been active, it just hasn’t been cold enough. We are looking for a mid-latitude cyclone to move in while we pull in some cold continental air from the north.
Swipe through the graphics that are provided by the Office of Water Prediction below. You can see the difference from northern Washington down south through Oregon. We are looking for that expansion of purple to cover southern Washington and Oregon. If you cycle to the second graphic, which is the scaled non-snow precipitation, you can see that we’ve had plenty of rain around the region just within the last 24 hours. That was the system that passed through this morning. All that moisture cuts off around the northern Oregon Cascades. This has also been a larger issue this November. We are fortunate for the rain, but it has been more concentrated to the north and west. We can’t get the snow machine going if we aren’t managing to tap into that moisture completely. The snow that we have brought up to the mountain has also melted due to that aforementioned warm air.
The following graphics will give an idea of how the general snow season plays out and where we are standing right now in late November. If you focus on the black line in the graphic below, that is where we are right now. We are riding very close to the minimum territory near the bottom. The median is the green line which is a gauge from 1991-2020. You can see that the line starts to increase around this time of the year, before reaching a peak around late February (145 days). We want that snow water equivalent to start jumping now until then. We are currently at a SWE of 2.2 inches where the median average for this time of the year is 7.3 inches. The max at this time of the year is actually 33.0 inches!
The second graphic is how the 2020 season played out versus the 30-year median. I just want to point out that you can see again how late November is just the start of this journey. Last year, the SWE dropped earlier, which opened the door for the start of our drought conditions this year.
It sure looks like we are going to start the month of December just about where we are now. I will note that there is some positive signs the second week of December for a pattern shift. The snowfall accumulation through Friday is tentatively bare for Oregon. A reminder that we are in a La Niña season, which is encouraging for more opportunities heading into the winter.