ChrisC
Well-known member
Watch for storms and 100 cm bases.....
Not an optimistic forecast for SA:
Not an optimistic forecast for SA:
South America 2025
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Those seasonal forecasts can be done as accurately by monkeys throwing darts, especially when there is no El Nino or La Nina.
Regardless of the forecasts, do not commit $$$ until adequate snow is on the ground. AFAIK Portillo has not had a season since 2009 that exceeded its 1971-2007 average.
Regardless of the forecasts, do not commit $$$ until adequate snow is on the ground. AFAIK Portillo has not had a season since 2009 that exceeded its 1971-2007 average.
That's sobering. Is that an anomaly or true for South America in general?
It is likely true for the latitude 33-35 areas Portillo, Valle Nevado and Las Lenas. Farther south the climate is different. It's a wetter and less boom or bust climate, but altitude is much lower so you have to worry about the rain/snow line.
ChrisC
Well-known member
LOL
Portillo is bringing its average snowfall down to 200" or so at the resort level. You have to commend them for honest reporting.
But where did 100" disappear to? Global Warming is changing weather patterns?
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Ski slopes with some of the best skiing in South America are to be found at the Portillo ski resort in Chile, for skiing and snowboarding
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ChrisC
Well-known member
My previous two trips to South America were more at the last minute, and I paid a bit more in airfare, but that's okay with me. Lodging and skiing are the same price.
I paid $1k instead of $700 for a round trip, which made the difference between exceptional snow and average snow.
I believe the climate models forecast drying out in some places at those latitudes. Portillo, despite its altitude, is an outlier in latitude at 32.8. Compare to lowest latitude ski areas in North America, Ski Apache NM at 33.4 and the rarely open Mt. Lemmon AZ at 32.4. Valle Nevado is 33.4. Las Lenas latitude is 35.1, similar to Arizona Snowbowl at 35.3.
I have high skepticism of climate models' regional predictions even though the big picture projections of overall world temperatures have been in the ballpark long term. We have covered this ground before. Since 2021:
Portillo had another lean year in 2022, 163 inches
256 inches in 2023 was about average but with only 72 inches by Aug. 13 it was not a good season overall.
261 inches in 2024 was also close to average but qualitatively better since 223 inches had fallen by June 25.
Some other updates to that post from 2021:
1) Alyeska had another excessively rainy season in 2024-25. The ratio of mid to upper snowfall was 52%, fifth lowest since 1979 and all of the other four were since 2015.
2) L.A. rain and SoCal snow were high in 2022-23 and 2023-24, but neither season met the standards of 2010 and prior excellent seasons since there was not much natural snow before February. 2024-25 in SoCal was only marginally better than the abysmal 2013-14 and 2017-18 seasons.
3) Taos had average seasons in 2022-23 and 2023-24 but its second driest ever season in 2024-25.
4) Utah has rebounded impressively. After one more below average season in 2021-22, it had record high snowfall in 2022-23 and the past two seasons were above average.
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ChrisC
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A decent start
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ChrisC
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You can see why you want to wait until there is snow on the ground in South America. Sometimes these mega-storms do not come to fruition, and it can be an abysmal season (many in the 2010s and 2020s).
When your average snowfall is 200-300 inches and you miss a 50-80" storm, that's a significant % of your overall snowfall for the season.
Same in California's Sierra, but most mountains receive more snow than the Andes, and Tony calculates less volatility.
When your average snowfall is 200-300 inches and you miss a 50-80" storm, that's a significant % of your overall snowfall for the season.
Same in California's Sierra, but most mountains receive more snow than the Andes, and Tony calculates less volatility.
Latitude explains a lot of this. Santiago is the same latitude 34 as L.A. and SoCal snow volatility is almost as high as Portillo's. Portillo gets more snow with altitude range 8,300 - 10,800 so minimal rain vs. SoCal ski elevation range 6,500 - 8,800.
Move to a more consistent storm track 37 latitude and the relationship above and rain incidence is the opposite. Chillan is 5,200 - 8,200 while Mammoth is 8,000 - 11,053.
ChrisC
Well-known member
If this storms cycle continues, it might be a good season for South America - at least Chile and Las Lenas.
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11 reactions | Jesus effing Christ it just nuked 4 feet (1.2 m) in 24 hours @nevadosdechillan in Chile! Around @skilaparva and @valle_nevado it left 20 - 24 in (50 - 60 cm) and 17 in (45 cm) @skiportillo. This storm delivered big time and an even big
Jesus effing Christ it just nuked 4 feet (1.2 m) in 24 hours @nevadosdechillan in Chile! Around @skilaparva and @valle_nevado it left 20 - 24 in (50 - 60 cm) and 17 in (45 cm) @skiportillo. This...
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ChrisC
Well-known member
Comparison between OpenSnow Forecasts and "Modeled" Snowfall History.
Note: OpenSnow does not retrieve actual snowfall totals from a storm. Instead, it uses another model that forecasts historical snowfall. Often, I find it simply backs up its forecast model.
All measurements for Portillo Elevations 9,450 ft.
From the Portillo Snow Report
skiportillo.com
Last Updated June 16th, roads are closed to Portillo.
From Portillo - Snowfall June 10 to 16th: 19 Inches
From OpenSnow - Snowfall June 10 to 16th: 30 Inches
As one can see, OpenSnow overestimates, this time by almost 50%.
Note: OpenSnow does not retrieve actual snowfall totals from a storm. Instead, it uses another model that forecasts historical snowfall. Often, I find it simply backs up its forecast model.
All measurements for Portillo Elevations 9,450 ft.
From the Portillo Snow Report
Snow forecast daily for Ski Portillo: snow, lift and road conditions
Snow forecast & Portillo snow & lift conditions updated daily. Skiing in Chile, South America from June to September. Full ski report here.
skiportillo.com
Last Updated June 16th, roads are closed to Portillo.
From Portillo - Snowfall June 10 to 16th: 19 Inches
From OpenSnow - Snowfall June 10 to 16th: 30 Inches
As one can see, OpenSnow overestimates, this time by almost 50%.
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ChrisC
Well-known member
Nevados de Chillan is looking very good. They open tomorrow - must have moved up the date - noe June 18th!
Hopefully, this updates.
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Hopefully, this updates.
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The computer weather models seem very prone to overstatement in the Chile/Argentina ski forecasts. https://www.snow-forecast.com/ has had this problem forever, and now that OpenSnow has expanded to South America in recent seasons, no surprise we see the same issues.
I agree with ChrisC that it's even worse to use a systematically overstated model to estimate past/historical snowfall.
OpenSnow is upfront about this methodology:
It happens sometimes in North America too. In-season I use a few OpenSnow season-to-dates for areas that don't show that info on their own websites. I had to stop doing that for Big Sky when I noticed OpenSnow was claiming as much snow there as at Targhee.
Compare to the end of season data I get from the mid-mountain patrol site.
I agree with ChrisC that it's even worse to use a systematically overstated model to estimate past/historical snowfall.
OpenSnow is upfront about this methodology:
OpenSnow shows daily snowfall calendars for 2024-25 for ski areas all over the Alps. I'll bet 95+% of these are from forecast models, not from resort reported snowfall.
It happens sometimes in North America too. In-season I use a few OpenSnow season-to-dates for areas that don't show that info on their own websites. I had to stop doing that for Big Sky when I noticed OpenSnow was claiming as much snow there as at Targhee.
| month | Oct. | Nov. | Dec. | Jan. | Feb. | Mar. | Apr. | |
| Big Sky patrol 2024-2025 snowfall | 15" | 58" | 49" | 55" | 70" | 53" | 35" | 335" total |
| Big Sky OpenSnow snowfall | 15" | 48" | 71" | 98" | 74" | 81" | 61" | 448" total |
Compare to the end of season data I get from the mid-mountain patrol site.
ChrisC
Well-known member
ChrisC
Well-known member
There is an asterisk or some marker/notification when they record an actual value. However, you are correct, almost 90% are estimates.
OpenSnow's historical snowfall estimates were reasonably in line with the storms I observed at Engelberg in late January and at Les 2 Alpes/Serre Che/Monterosa in early April.
What is a bit sad:
Higher elevation resorts (France, Aosta, W. Switzerland) likely had an above average snow year thanks to a strong early and late season: Typical French Mega Resort (Nov-50", Dec-100", Jan-100", Feb/March - 25-50" for both months, April/May-100"). The only period that was particularly challenging was from mid-February to mid-March.
Almost all had totals in the 300-350 inch range (Les 2 Alpes - 400").
Austria and the Dolomites were a disaster overall, with only 33-50% of the Western Alps' snowfall.
Ischgl - 130"
St. Anton - 200"
Lech - 240"
Saalbach -130"
EMSC
Well-known member
You mean 100% (42 forecast is more than 100% more than the 19" received)?
Computers have always been great at GIGO! Yet another reason true AI is a ways off. It'll speed a lot of things up for now (fewer workers needed, but not absolute replacement of humans). But basically everything has to be checked over by humans for all the errors AI generates.