Originally Posted by Gpaul
Not meaning to hijack, but just having been in the Tahoe "rain", and seeing this crop up again, would anyone care to expound on the Historical rainy winter days in Tahoe and/or West Coast vs., say, Mammoth, and Utah, Colorado?
Is this rain thing a west coast low altitude phenomenon?
Happened to us at Whistler in January a few years ago, but were at Sun Peaks just a few days prior to WB and not 1 drop of rain!
OK, here's the deal as best as I can explain it:
- Altitude and Latitude play large roles in Western skiing. Obviously, the further south you go, the higher base elevation you need to stay above the snow line. Draw a line across the Western US from about Tahoe through Colorado. It roughly goes through Tahoe, below Salt Lake and through Denver, so these are areas that serve as a sort of baseline for resort base comparison. For instance, Tahoe resorts have bases in the 6,000' range (K'wood & Mt. Rose higher), the Salt Lake resorts from 7,000' to 8,500' and the Colorado resorts in the 8,000 to 9,000' range (Loveland, Apapahoe higher). Now all other things being equal, Tahoe generally gets more rain than either Salt Lake or Colorado (Salt Lake equalizes w/ Colorado due to its higher latitude). Going further south, Mammoth has an 8,000' base and gets less rain than Tahoe, even though it lower latitude (not that much further south). Jackson Hole does well too, with a 6,000' base but is considerably further north than SLC, as does Sun Valley. Big Sky with a base of 7,000' and far further north than SLC, is an almost sure bet for snow all the time. In SoCal, I don't know how the Big Bear resorts ever manage to stay open with base elevations of 7,000', but a very low latitude. Up north in the Seattle area, Mt. Baker does considerably better than the Summit resorts with 4,000' vs. 3,000' bases, respectively.
- The other factor is local weather patterns. The further you go towards the interior, the drier and colder the over-riding air above gets. If you look at the 700mb atmosperic temperatures across the US, the coldest pocket of air in the winter resides in a swath from Idaho to Montana, down through Wyoming, and the Top halves of Utah and Colorado (another cold pocket resides over Northern Maine too). This colder pocket of air tends to cool warmer pacific storms somewhat as they travel across the interior (Rockies), after crashing into Tahoe. The Rockies also have additional adiabatic cooling and topographical orographic cooling after the storms cross the relative lower/dry lands of the Great Basin. This is epecially pronounced in Utah, where rain is indeed a rare word at places like Alta/Bird, Solitude & Brighton.
So there you have it. I would arrange in following order, rain adverse Western Resorts:
1) Big Sky, MT
2) Grand Targhee
3) Loveland, CO
4) Arapahoe, CO
5) Alta, UT
4) Brighton, UT
5) Snowbird, UT
6) Solitude, UT
7) Breckenridge, CO
8) Kirkwood, CA
9) Mammoth, CA
10) Copper Mt, CO
I would say any of the above list would be pretty safe at any given time to avoid rain.