There were some times this week when the hype train, regarding the upcoming weather systems, was running so fast that it was only a matter of time before it ran off the rails. There were some models showing the potential for as much as 10 feet of snow by the end of next week. The only problem with those forecasts was that they failed to mention the atmospheric river that could have sent snow levels higher than Ward Peak at Alpine Meadows. Fortunately, I never boarded the hype train this week, being a bit too busy with other projects to do more than take a casual glance at the models. The hype train derailed this morning and forecasts are looking much more typical for an early season La Niña event in the Sierra.
There’s two systems rolling in for the weekend. Similar to last weekend, the first wave is just about disappearing from the models, bringing mostly clouds and cooler temperatures for Thursday night into Saturday. On Saturday, the stronger of the two storms will move in, bringing a better chance of rain and snow to the Sierra. Yes, this system is taking a more zonal approach across the Pacific, meaning that snow levels will be much higher than last weekend. As of now, snow levels should be around 7K feet. I prefer that to earlier forecasts, which put them at 9k feet and higher.
Wednesday update: The first storm is totally gone now. The timing has moved up on the second wave. Expect things to ramp up late Friday afternoon and be pretty much done by Saturday morning.
We should end up right at the southern end of the storm, with precipitation and colder air just barely making it to the Northern Tahoe area. As is typical in strong La Niña years, the Southern Sierra and most of California could be shut out by this system, and the next one as well. Last weeks system was more of an anomaly with its northern flow. The last run of the GFS was a bit bearish on the weekend storm, showing the potential for 0.75 to 1 inch of moisture, which could bring a foot of snow to the crest in North Tahoe. Some of the other models are trending a bit more generously.
A third system is on tap for about next Tuesday. A couple of days ago it looked like it could be a huge AR type event. The tap to subtropical moisture seems to be lost on today’s models runs. I call that a win, as it could have washed out much of the progress being made by snowmaking crews on the lower parts of the mountain. On today’s runs, the Tuesday event looks very similar to the weekend storm, with the potential to bring another 1 foot, or more of snow.
Wednesday update: We’re off the rails and in the ditch on this one. It’s disappeared and has been replaced with increased ridging and warmer temperatures…ouch.
It’s probably a good thing that these next storms are coming in just a bit warmer. Our early season snowpack was getting set up for a significant avalanche problem later in the season. We had a very light and dry snowfall last weekend, which in itself doesn’t bond that well to the ground below. It’s been followed by several very cold and clear nights. Those conditions are perfect for the formation of facets and surface hoar. If another cold storm comes in and dumps snow on top of that, you have a snowpack sitting on top of a very weak layer.
Fortunately, within the confines of a ski resort, avalanche control work by ski patrol can reduce the risk of those weak layers. But they can’t eliminate the risk entirely. More importantly, consider all of those first time backcountry skiers, the ones that are hoping to avoid the ski resort scene entirely this year. For all of us, I would be happy to see this next system come in just a bit wetter to tamp down that weak layer and build a better bond.
We’re still in the transitional part of the season. The weather models are least proficient at their predictions as we transition from quieter fall conditions to a more active winter pattern. I would expect that we will still see some changes in the forecast totals as the storms arrive. I’m happy to be somewhere in the middle, not with 70° temperatures or a deluge of rain. The calendar says we’re 15 days from a scheduled opening at SVAM and we have our fingers and toes crossed.
Who you calling a hoar?
U so funny!