Annette McGee Rasch – IVN Senior Contributing Writer
Has this past winter been one for the record books? Not really. Not in terms of actual precipitation totals for much of southwest Oregon – though it’s been another story in California.
Still, it’s been an “unusual” winter throughout Oregon, said National Oceanic and Atmospheric Administration meteorologist Mike Petrucelli.
December and January brought seemingly nonstop “atmospheric rivers off the Pacific Ocean” that zeroed in on central California and also had strong impacts on southwest Oregon. This same weather pattern continued to hammer parts of California throughout February and March, though in Oregon, the weather took more of an arctic turn.
“The cold showers and low snow levels since mid-February came from a persistent trough,” Petrucelli said. “This long pattern of lower air pressure brought storms into the Pacific Northwest that originated in the Gulf of Alaska.” Some of that arctic air also pushed snowy weather into southern California.
This past winter’s weather has helped much of the west cope with years-long drought conditions. NOAA now reports that the western half of Josephine County is no longer in drought conditions and the east side of JoCo is designated as “abnormally dry.” Though heading farther east, while conditions are improved, NOAA says nearly all of Jackson County remains in “moderate drought” status.
As of April 1, the Emigrant Lake reservoir near Ashland, which was very low, has now filled to 41% of normal.
Agate Lake reservoir, 13 miles northeast of Medford, is up to 94 percent! Though the Hyatt reservoir is only 19 percent full; and Howard Prairie currently sits at 21 percent of normal.
“Some of the reservoirs are still pretty low, but compared to where they were, the situation is much better – and keep in mind that as more snow melts, those southwest Oregon reservoirs will fill more,” Petrucelli said. He also noted how many of California’s water reservoirs are now at almost normal levels.
In meteorology, the ‘snow-water equivalent’ describes the equivalent amount of liquid water stored in snow. The current snowpack throughout the region is “looking good” at 152 percent of normal, Petrucelli said. And at Crater Lake, as of April 1, the snow depth was reported at 160 inches at the park’s visitors center.
Precipitation is measured in what meteorologists designate as a ‘water year,’ which in this region begins on October 1 and runs through September 30.
This year’s water year so far has brought 62.68 inches of precipitation in O’Brien, according to Gordon Lyford, a retired BLM scientist who has been collecting weather data at his O’ Brien residence for 30 years. (Keep in mind that precipitation totals drop dramatically as measured farther inland.)
“Average annual rainfall totals in O’Brien are about 80 inches; then in Cave Junction that number goes down to about 60 inches,” Lyford said. “Then in Selma, the precipitation average drops to about 55 inches. In Grants Pass it goes down to around 30 inches; and in Medford, they only get an average of 18 inches of rain a year.”
By “normal” or “average” Lyford refers to an average within his 30-year data collection. “When I started measuring, we got about 82 inches a year, but it’s been going down a little. Now it’s closer to 78 inches annually – so that’s about a 5% decrease.”
Lyford said in April, the O’Brien precipitation average is about 8 inches; while four inches is normal for May; and for the rest of the season, only about 2 inches of rain typically falls. “You could say that average precipitation for O’Brien from April 1 through September 30 is about 14 inches,” Lyford said.
So heading into April, with an O’ Brien total of 62.68 inches accumulated so far, it seems likely that this current water year might end up just shy of a normal value – especially as the experts at NOAA’s Climate Prediction Center say the three-month outlook for southwest Oregon is leaning slightly below average for precipitation.
Though it’s best not to take bets on the weather… note how the spring of 2022 was also unusual: 11 inches of rain fell in O’Brien in April; 5.3 in May; and 2.25 in June – heck, it even rained on July 4. That late rain was welcomed, as it brought the 2021/22 water year totals up to 65.14 inches of precipitation, which was a little over 80 percent of normal precipitation for O’Brien.
Finally, what’s really remarkable is what happened this past year in California: with the highest ever recorded snow pack levels in the high Sierra’s. Lake Tahoe is at record levels.
Lyford said the previous records were for 1982-83 with precipitation at 230 percent of normal. “Right now they’re at 300 percent of normal of precipitation, they got 700 inches of snow at Mammoth Mountain ski resort!”
But it’s April now – spring has to be coming, right?