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Winter 2026-27 · Method v1.0 · Frozen 2026-08-19

The SnowSure El Niño Prediction Ledger

Recorded August 19, 2026 · Method v1.0 · This document does not get edited. It gets graded.

NOAA CPC, August 2026: >90% probability of a very strong El Niño; 69% chance the Oct–Dec index exceeds anything since 1950. Our signal: each resort's average snowfall in the three strongest El Niño winters ('97-98, '15-16, '23-24) vs its own 30-year ERA5 baseline. n = 3 — a lean, not a law. That honesty is the point of grading it.

Machine-readable JSONLive grades APIMethod v1.0

Headline hit rate

—/12

Nothing graded yet. Andes closes first week of December.

Fleet HIT / PARTIAL / MISS

0 / 0 / 0

139 still open

Locked fleet

43·22·22·17·35

A / B / C / D / E · 139 ranked

The twelve headline predictions

Each is falsifiable. Criteria locked August 19, 2026 — before a single flake falls in the Northern Hemisphere. Prediction 12 is not a hedge on the others. It is a prediction about variance itself.

#PredictionGraded HIT ifMeasuredGraded
1The Andes finish their 2026 winter above average(Portillo, Las Leñas, Valle Nevado, La Parva basket)basket ≥ +10%+26%InterimDec 2026
2Utah finishes above average(Alta + Snowbasin)basket ≥ +5%—PendingJun 2027
3Tahoe finishes above average(Palisades + Heavenly + Kirkwood)basket ≥ +5%—PendingJun 2027
4The high Alps finish above average(Zermatt, Arlberg, Val d'Isère, Grands Montets, Andermatt)basket ≥ 0%—PendingJun 2027
5Colorado stays ENSO-proof(Vail + Aspen Mountain)basket within ±10%—PendingJun 2027
6Washington runs below average(Mt. Baker + Crystal)basket ≤ −5%—PendingJun 2027
7Interior BC runs below average(Revelstoke + Fernie)basket ≤ −5%—PendingJun 2027
8Japan's totals run below average(Niseko, Furano, Nozawa, Happo-One) but the trip survives: Niseko logs ≥ 85% of its normal snow-day countbasket ≤ −5% AND Niseko snow days ≥ 85% of its 30-yr norm—PendingJun 2027
9The Pyrenees run below average(Baqueira)≤ −5%—PendingJun 2027
10The Northeast runs below average(Killington)≤ −5%—PendingJun 2027
11Whistler Blackcomb shrugs it offwithin ±10%—PendingJun 2027
12The pattern-breaker clause: at least one of predictions 2–11 misses in the opposite direction, because that's what strong El Niños doself-grading—PendingJun 2027

The full-fleet prediction (139 resorts)

Every ranked resort carries a predicted tier, locked today: 43 A (Prime) · 22 B (Favored) · 22 C (ENSO-proof) · 17 D (Late bloomer) · 35 E (Deep timing play). Season total vs own 30-year average:

Predicted tierHITPARTIALMISSLive
A · 43≥ +5%−5% to +5%≤ −5%0/0/0
B · 22≥ 0%−5% to 0%< −5%0/0/0
C · 22within ±10%—outside ±10%0/0/0
D · 17≤ 0%0% to +5%> +5%0/0/0
E · 35≤ −3%−3% to +5%> +5%0/0/0

Measurement protocol (locked)

  • Data: the same ERA5-based season totals as the signal itself — measured against each resort's own 30-year average, never against another resort or a marketing total. Snow-day counts for prediction 8 from the same archive.
  • Windows: SH season = Jun 1–Nov 30, 2026, graded first week of December 2026. NH season = Sep 1, 2026–Jun 30, 2027, graded first week of June 2027.
  • Grader: automated (scheduled runs already created), published regardless of outcome. Interim standings appear in the weekly in-season scorecard (Dec–Mar) so the final grade is never a surprise.
  • No edits: this ledger and predictions-2026-27.json are frozen as of August 19, 2026. If we ever change a threshold, the change gets its own dated line and the original stays visible.

Why we're doing this

Every ski account will make El Niño predictions this fall. To our knowledge, none has ever published its scoring rules in advance and graded itself in public. If we're right, the receipts are the marketing. If we're wrong, the post-mortem is the content — and next year's model gets better. Either way, "SnowSure grades its own forecasts" becomes the sentence that separates us from every repost account in the feed.

First grade lands early December 2026 — the Andes verdict.

Locked ranks

RankResortTierPredictedMeasuredGrade
#1PortilloA+81%+45%Interim
#2Las LeñasA+66%+29%Interim
#3Valle NevadoA+60%+14%Interim
#4La ParvaA+60%+14%Interim
#5Alyeska ResortA+20%—Pending
#6The RemarkablesA+20%−74%Interim
#7AndermattA+19%—Pending
#8Monterosa SkiA+17%—Pending
#9Coronet PeakA+17%−78%Interim
#10CourmayeurA+15%—Pending
#11La GraveA+15%—Pending
#12SnowbasinA+15%—Pending
#13Madonna di CampiglioA+14%—Pending
#14La ThuileA+14%—Pending
#15Engelberg-TitlisA+13%—Pending
#16Nevados de ChillánA+13%+27%Interim
#17Grands Montets (Chamonix)A+13%—Pending
#18LaaxA+13%—Pending
#19AltaA+12%—Pending
#20GulmargA+12%—Pending
#21La RosièreA+12%—Pending
#22DavosA+11%—Pending
#23Portes du SoleilA+11%—Pending
#24Cerro CatedralA+11%−43%Interim
#25GstaadA+11%—Pending
#26Ski Arlberg (St. Anton)A+11%—Pending
#27VerbierA+10%—Pending
#28Deer Valley ResortA+10%—Pending
#29Park CityA+10%—Pending
#30IschglA+10%—Pending
#31Ski Santa FeA+10%—Pending
#32Sugar BowlA+10%—Pending
#33MéribelA+10%—Pending
#34Alpe d'HuezA+9%—Pending
#35Palisades TahoeA+9%—Pending
#36CardronaA+9%−67%Interim
#37KirkwoodA+9%—Pending
#38Les ArcsA+9%—Pending
#39Sierra at TahoeA+9%—Pending
#40Val ThorensA+9%—Pending
#41AvoriazA+9%—Pending
#42Powder MountainA+9%—Pending
#43Taos Ski ValleyA+8%—Pending
#44Saas-FeeB+8%—Pending
#45HeavenlyB+8%—Pending
#46SöldenB+7%—Pending
#47St MoritzB+7%—Pending
#48Val GardenaB+7%—Pending
#49LivignoB+7%—Pending
#50Val d'IsèreB+7%—Pending
#51TignesB+7%—Pending
#52Steamboat Ski ResortB+6%—Pending
#53PalandökenB+6%—Pending
#54MegèveB+6%—Pending
#55Alta BadiaB+6%—Pending
#56La PlagneB+6%—Pending
#57CerviniaB+6%—Pending
#58Zermatt / MatterhornB+6%—Pending
#59CorralcoB+5%−5%Interim
#60Winterpark ResortB+5%—Pending
#61Arapahoe BasinB+5%—Pending
#62GrindelwaldB+4%—Pending
#63Cortina d'AmpezzoB+4%—Pending
#64Courchevel 1850B+4%—Pending
#65Hintertux Glacier Ski ResortB+4%—Pending
#66Crested ButteC+3%—Pending
#67GudauriC+2%—Pending
#68SilvertonC+2%—Pending
#69Beaver CreekC+2%—Pending
#70Mt. BachelorC+2%—Pending
#71BreckenridgeC+2%—Pending
#72FormigalC+2%—Pending
#73Aspen MountainC+1%—Pending
#74ZaoC0%—Pending
#75KeystoneC0%—Pending
#76Sun ValleyC0%—Pending
#77VailC−1%—Pending
#78SnowmassC−1%—Pending
#79TellurideC−1%—Pending
#80Copper MountainC−1%—Pending
#81FolgefonnC−1%—Pending
#82VossC−2%—Pending
#83Big WhiteC−2%—Pending
#84Limone PiemonteC−2%—Pending
#85Whistler BlackcombC−2%—Pending
#86Mammoth MountainC−3%—Pending
#87Jackson HoleC−3%—Pending
#88KitzbühelD−3%—Pending
#89Mt HuttD−4%−32%Interim
#90Whitewater Ski ResortD−4%—Pending
#91SugarbushD−4%—Pending
#92Wolf Creek Ski AreaD−5%—Pending
#93Happo-One (Hakuba)D−5%—Pending
#94Big SkyD−5%—Pending
#95Shiga KogenD−5%—Pending
#96MadaraoD−6%—Pending
#97StoweD−6%—Pending
#98StrynD−6%—Pending
#99Jay PeakD−6%—Pending
#100Brundage MountainD−7%—Pending
#101KillingtonD−7%—Pending
#102Grand Targhee ResortD−8%—Pending
#103ÅreD−8%—Pending
#104Mt. Hood MeadowsD−8%—Pending
#105White PassE−9%—Pending
#106Bridger BowlE−9%—Pending
#107NaebaE−9%—Pending
#108Eaglecrest Ski AreaE−10%—Pending
#109Timberline LodgeE−10%—Pending
#110KaguraE−10%—Pending
#111Crystal Mountain WAE−10%—Pending
#112Stevens PassE−11%—Pending
#113Mt. WashingtonE−11%—Pending
#114MyokoE−11%—Pending
#115Schweitzer MountainE−11%—Pending
#116Kicking Horse Mountain ResortE−11%—Pending
#117FernieE−12%—Pending
#118RevelstokeE−13%—Pending
#119Appi KogenE−14%—Pending
#120Lotte AraiE−14%—Pending
#121KiroroE−14%—Pending
#122Kamui Ski LinksE−14%—Pending
#123SasquatchE−14%—Pending
#124RusutsuE−15%—Pending
#125Baqueira BeretE−15%—Pending
#126Mt. BakerE−15%—Pending
#127Niseko Grand HirafuE−15%—Pending
#128Lake LouiseE−15%—Pending
#129FuranoE−15%—Pending
#130Marmot BasinE−16%—Pending
#131RiksgransenE−16%—Pending
#132GrandvaliraE−16%—Pending
#133Summit at SnoqualmieE−17%—Pending
#134Nozawa OnsenE−17%—Pending
#135TomamuE−19%—Pending
#136NarvikE−21%—Pending
#137Whitefish Mountain ResortE−22%—Pending
#138Shames MountainE−22%—Pending
#139ThredboE−34%−28%Interim