Challenges

It was day two of this young Alpine Meadows ski season and I am so appreciative to be back on our home hill. The snow was looking and feeling much more winter like this morning. There was snow on the trees. Ski Patrol pushed out a few boundary lines, opening up that little strip just lookers left of the lift line before the mid-station. (Somebody told me the name of that last season but I cannot find it now.) Also, the closure signs moved closer to the creek on the right on the skiers right part of Weasel, opening a bit of off piste terrain. You are asking for a core shot in that zone right now.

The new snow was fantastic where the overnight groomers had turned it into corduroy. The ungroomed snow was a bit crusty and challenging for those that felt a need to make turns. After a few runs, that was no longer an issue.

One of the challenges of today was that we are not the only people that wanted to ski today. It was a weekend day, and the start of a vacation week for many people. A lot of people wanted to ski today and demand exceeded supply. The Weasel Run was a bit frightful as crowds peaked mid-morning. There were plenty of people out there trying to prove that they were the best skier or boarder on the mountain. Unfortunately, with so little terrain open, there was not a good way to escape from that. Once the TLC line was out of the small corral, I called it a day.

Thanks to the mountain ops staff at Alpine Meadows for your efforts. You all rock!

A Challenging Weather Forecast

Things have not turned out exactly as we expected from this set of storms in the Sierra. Down along the coast, there has been some very large amounts of rain, equating to a “100 year storm” for rainfall in most locations. But in the Sierra we have seen a lot of wind, but not as much rain or snow as predicted. There are a lot of different things that might affect how things pan out for an AR event. Going back to the radar & satellite image I posted the other day, typically you have a cold front that is aligned with the jet stream. You expect the that low pressure area to drive that cold front south and east in a progressive line. As the front passes, the colder air in the low is often what brings us a lot of snow toward the end of the event. That’s not what happened this time.

The Pacific Ocean has been very active weather wise over the last couple of weeks. As an example there were four typhoons in a row that affected the Philippines in 10 days in early November. For this week, we actually had two different cold lows in the Gulf Of Alaska. Instead of moving toward the south and east, those low pressure systems rotated around each other, causing that cold front to stall over the Bay Area and points north, leaving us mostly on the warm side of the jet. Here’s a cool animation showing the flow of the water vapor in those systems.

This upper-level water vapor satellite loop shows the interactions between a pair of low pressure centers in the northeastern Pacific since late Wednesday night! #CAwx #ORwx #WAwx pic.twitter.com/U3Uqf6ZrtS

— RadarOmega (@RadarOmega) November 22, 2024

That rotation of one low around another is called the Fujiwhara Effect and it’s relatively rare, generally happening once a season or less in the Gulf of Alaska. You can see in the video how that rotation pulls the cold front away from the Tahoe area, causing the warmer temperatures we saw Friday night and Saturday.

As the cold front sagged southward this morning, we saw a more significant return to snow for Tahoe. Mount Rose reported 13-18 inches and Palisades Tahoe reported about 10-11 more inches toward the top of the mountain. At the base of the mountain at Alpine Meadows, the morning photos showed 3-4 inches of new snow on the Sun Deck and that is a whole lot better than rain.

Theoretically we will get a short break tomorrow before the last system moves in Sunday night into Tuesday morning. Here’s the Winter Storm Warning from the Reno office of NOAA. I like the snow part, I could do without the wind part. More and more, all significant Sierra storms include these high winds. One mountain source I talked to yesterday mentioned that when they started, 100+ mph winds only happened a few times each season. It’s absolutely more frequent now, happening with just about every WSW event.

Looking further into the future, most of the models are calling for a significant drying trend. Here’s the 8 to 14 day outlook for precipitation:

And here is the PNA forecast, showing most of the models trending positive, indicating ridging in the Pacific.

This is not ideal for the Mountain Ops people that are trying to get more of the mountain open for us, or for those of us that are looking forward to having more of the mountain open. That said we are far better off than the areas in the east, where most mountains are still sitting dry and the danger of forest fires is still uncomfortably high. Fortunately, it looks like the fire season has been put to rest in Tahoe and the Northern Sierra. There’s still some concerns in the Southern Sierra and SoCal in general. This next storm should dampen things a lot as the jet stream focuses more toward Mammoth on Monday.