#snowpack-variability

#snowpack-variability

The storm cycle will bring 8-17 inches of new snow to most open resorts in the PNW, with snow quality starting dense to moderate on Tuesday and improving as colder air arrives on Wednesday.

Mammoth Mountain reported between 12 and 18 inches of new snow over the past 48 hours, with additional snowfall forecasted to add to an already solid late-season base.

The ski season in Colorado is being described as the worst in 50 years, with resorts opening less than half their usual terrain for much of the winter.

Oregon starts with denser snow and the best near-term accumulation at Mt. Bachelor and Timberline, then the whole Cascade chain turns colder as snow levels fall toward and below pass level during the midweek system.

If the lake level drops below 3,490 feet - termed the minimum power pool - the turbines that generate electricity have to be shut down. When the water level reaches critically low thresholds, air is sucked down like a whirlpool into the penstocks, forming explosive bubbles which can cause massive failure inside the dam.

The storm will begin warm and wind-affected on Friday, with snow levels starting around 7,000 to 8,000 feet, leading to wet conditions at lower elevations initially.

SWE is the most important metric for all of our water resources. It's the metric that we deal with the most and the one that the entirety of the snow research and operations community is working to get right. So, seeing an increase in SWE like that, even if it's from mid-winter rain, is a great thing because that means we have more water stored in the snowpack moving forward.

Avalanches kill about 100 people in Europe each year, with vast masses of ice, snow and rock regularly crashing down on hikers and skiers who have been caught unawares. The structure of the snow, angle of the slope and variation of the weather can dictate whether a gentle disturbance like a gust of wind or the glide of a snowboard can trigger a deadly shift in the mountain.

"A dry January, which is historically the wettest month of the year in California, has now eroded the gains made at the start of the year and forecasts currently show no major precipitation in the next two weeks," California Department of Weather Resources spokesperson Jason Ince wrote in a Jan. 30 news release. The first month of the year certainly left the area warmer and drier than usual, weather officials confirmed.

To get back to average snowpack, we essentially need to have the most snow that we've ever had for the last 30 years between now and mid-April. It would be extremely difficult for Colorado to get back to a normal/average snowpack. As an example, when looking at the Independence Pass SNOTEL site in central Colorado outside of Aspen, we typically have 13 inches of snow-water-equivalent at the end of February. This year, we only have 6.7 inches of SWE.

Confidence is highest through Saturday because the individual models agree well on the timing of the Thursday storm and the following break. Southern California's mountains pick up a quick shot of snow on Thursday with strong winds, then dry out into the weekend. Beyond the weekend, the signal stays active, but model spread grows fast on storm timing, snow levels, and wind impacts, so expect meaningful swings from run to run.

Sun night (02/15) through Tue night (02/17) is the core punch, and many Sierra mountains can stack 20″-50″ in that window as snow levels crash. Expect a lighter start Sunday night, then snowfall rates ramp up hard Monday night into Tuesday with widespread coverage across Tahoe, the central Sierra, and down into Mammoth. Snow levels begin around 5,000 to 5,500 feet early, then fall into the 1,500 to 2,500-foot range by Tuesday and Tuesday night, which helps keep even lower terrain in play for all-snow.