Short Answer

Mammoth Mountain snowfall exceeding 35 inches by December 24th is likely, driven by strong El Niño forecasts; the market prices this outcome at 92%.

1. Market Behavior & Drivers

This market's primary movement was a price collapse on November 13, when the probability of Mammoth Mountain receiving over 35 inches of snow by December 24 fell 86 percentage points, from 95.0% to 9.0%. While a significant Sierra storm was forecast around this date, the severe negative price action indicates the storm either failed to deliver its expected 1-2 feet of snow or that forecasts were sharply downgraded. This repricing erased earlier optimism and aligned the market with the reality of a below-average snowpack. The move occurred on minimal volume, with only 0.01 contracts traded.
The preceding climb from 5.0% on October 31 to 95.0% by November 8 occurred on zero reported volume. This suggests the initial high probability was not the result of broad market conviction but rather speculative positioning in an illiquid market, likely based on long-range weather outlooks.
The current 9.0% price reflects the reported conditions as of November 14. With a season-to-date total of just 12 inches and a snowpack running 29% below average, the mountain requires at least 23 more inches of snow in approximately 40 days to meet the contract's threshold.
  • Market probabilities favor above 35-50 inches, supported by OpenSnow's 45-inch Thanksgiving forecast. Octagon views 140+ inches as overly optimistic given current low snowpack and El Niño forecasts.

Who Wins and Why

Outcome Market Model Why
Above 165 inches 9.0% 6.0% Despite strong El Niño forecasts, current low snowpack appears to require significant accumulation by December 24th.
Above 50 inches 82.0% 90.0% Despite strong El Niño forecasts, current low snowpack appears to require significant accumulation by December 24th.
Above 140 inches 98.0% 84.8% Despite strong El Niño forecasts, current low snowpack appears to require significant accumulation by December 24th.
Above 95 inches 50.0% 84.8% Despite strong El Niño forecasts, current low snowpack appears to require significant accumulation by December 24th.
Above 125 inches 24.0% 84.8% Despite strong El Niño forecasts, current low snowpack appears to require significant accumulation by December 24th.

Current Context

Mammoth Mountain currently reports low snowfall, but significant storms are imminent. As of November 14, 2026, Mammoth Mountain Main Lodge has recorded a season total of 12 inches (3" in October, 9" in November), with a base depth of 12 inches [1][2][3][4]. Only 2 of 25 lifts are open, and the snowpack is at -29% of the average for November 13 [1][2][3][4]. The 2026-27 season opened on November 7, 2026 [2][5]. A storm warning issued on Friday, November 13, indicated significant snowfall through the night of November 14, leading to a delayed opening [1][6]. OpenSnow forecasts heavy snow and strong winds from Storm #1 on Friday, followed by a break over the weekend, Storm #2 on Monday, Storm #3 on Wednesday/Thursday, and potentially more active weather during Thanksgiving week [1][6].
Forecasts predict an El Niño-driven "big snow year" for Mammoth. OpenSnow meteorologist Alan Smith's 2026-27 forecast anticipates a record El Niño, with sea surface temperature anomalies of 3.5–4.5°C expected by early winter [7][8][9][10]. This is projected to result in above-average snowfall across the Sierra Nevada, including Mammoth, with the strongest signal anticipated from January through March [7][8][9][10]. Outside Online described Mammoth as "pretty much a lock for a big snow year" [8]. Historically, December 24 snowfall totals have ranged from 2 inches (2011-12 season) to 209 inches (2010-11 season), averaging approximately 67 inches [2][11][12][13]. The 2022-23 season recorded 138 inches by December 24, which was 150% of normal, with 96% of the mountain open [2][11][12][13]. That season ultimately became Mammoth's record, with 715 inches at Main Lodge and approximately 900 inches at the summit [2][5][14]. The 2016-17 season, for instance, saw 12 inches by early December before a 3-4 foot storm on December 15-16, followed by another 17 inches on December 23-24 [2][11][12][13]. The 2025-26 season totaled 297 inches, slightly exceeding the 286 inches in 2024-25, despite a delayed November 20 opening [2][5][14]. The 2026-27 season is scheduled to close on May 30, 2027 [2][5][14].
Prediction markets show high probability for above-average December snowfall. The Kalshi market (kxmammothsnow-24dec26) resolves on cumulative Main Lodge snowfall from October 1 to December 24, 2026, recorded at 4:00 PM ET [15][16][17]. A November 14 snapshot of market odds indicated 95.5% for Above 35", 87% for Above 50", 75% for Above 65", 63% for Above 80", and 50% for Above 95" [15][16][17]. Approximately $13,347 in volume was observed on the 80"/95" brackets [15][16][17]. OpinionKings, as of November 12, 2026, listed a 99% probability for Above 140 inches by December 24, using data from OnTheSnow, WSJ, and Alterra Mountain Company [18]. This 140-inch threshold is significantly higher than Kalshi's top listed brackets, suggesting a divergence in market expectations for the upper tail of snowfall totals [18].
Sources (18)
  1. 1Mountain Report | Mammoth Mountainmammothmountain.com
  2. 2Snowfall History | Mammoth Mountainmammothmountain.com
  3. 3Mammoth Mountain Snow report - Freeridefreeride.com
  4. 4Mammoth Mountain Snow Report | OnTheSnowonthesnow.com
  5. 5Mammoth Mountain Snow Report | Current Conditions | SnowStashsnowstash.com
  6. 6Mammoth Mountain Snow Forecast | OpenSnowopensnow.com
  7. 72026-2027 Winter Forecastyoutube.com
  8. 8The Forecast Is in for a "Supersized Wild Winter." These Towns Will Get the Most Snow.outsideonline.com
  9. 9Tahoe’s winter forecast is looking snowy | TahoeDailyTribune.comtahoedailytribune.com
  10. 10El Niño Forecast Is ‘Off the Charts.’ What Could This Mean for Ski Season? | KQEDkqed.org
  11. 11Mammoth Mountain Snow History | OnTheSnowonthesnow.com
  12. 122016-17 California Detailbestsnow.net
  13. 132022-23 Ski Season Progress Reportbestsnow.net
  14. 14Mammoth Mountain Records More Snow in 2025-26 than 2024-25snowbrains.com
  15. 15Mammoth Mountain snowfall total by December 24th | PredictPediapredictpedia.com
  16. 16Mammoth Mountain snowfall total by December 24th — Live Oddspredictionmarkets.us
  17. 17Snow & Rain Prediction Markets | Kalshikalshi.com
  18. 18Mammoth Mountain snowfall total by December 24th · OpinionKingsopinionkings.com

2. Price Chart

Historical Price (Probability)

Outcome probability
Date

3. Significant Price Movements

Notable price changes detected in the chart, along with research into what caused each movement.

Outcome: Above 165 inches

📉 November 13, 2026: 86.0pp drop

Price decreased from 95.0% to 9.0%

What happened: The primary driver for prediction market activity on November 13, 2026, was a significant Sierra storm that hit Mammoth Mountain, forecast to deliver 1-2 feet of new snow and potentially raising the season total to around 86 inches [1]. However, the reported "86.0 percentage point drop" for the "Above 165 inches" outcome is mathematically impossible, as the market was trading at only 8-9% probability, and increased snowfall would logically boost its price [2]. This suggests an error in the described market movement. Social media was a contributing accelerant, as news and forecasts for the storm generated widespread attention and likely increased market volume [3].

Outcome: Above 125 inches

📉 November 11, 2026: 10.0pp drop

Price decreased from 89.0% to 79.0%

What happened: The prompt indicates a 10.0 percentage point drop for "Above 125 inches" on November 11, 2026; however, the provided research consistently details events and forecasts that would typically drive a price increase for this market's probability [4]. Specifically, Eastside Weather's update on November 11 forecast a potent cold front bringing 6-10 inches at Main Lodge and a colder follow-up storm, following Mammoth Mountain's early opening on November 5 due to prior snowfall [4]. No specific social media activity from key figures or viral narratives promoting reduced snowfall expectations on November 11, 2026, appears in the provided research to account for such a drop [4]. Therefore, social media was irrelevant, and the available information strongly suggests an upward price movement during this period, contradicting the stated drop.

Outcome: Above 80 inches

📈 November 06, 2026: 64.0pp spike

Price increased from 25.0% to 89.0%

What happened: The available market history for the "Above 80 inches" outcome does not support a 64.0 percentage point spike on November 06, 2026; rather, it showed a 24-hour decline of 26 percentage points at a later snapshot [5]. Consequently, identifying a primary driver for the reported upward price movement is not possible, as the movement itself is unsubstantiated by the provided sources [6]. Social media's role cannot be assessed without evidence of the specified price movement.
Sources (6)
  1. 1Sierra Nevada storm watch: up to 2 feet of snow from Friday 13 Novemberpick-a-ski.com
  2. 2Mammoth Mountain snowfall total by December 24th Odds & Predictionskalshi.com
  3. 3Snow Before You Go: Sierra Powder Today, a Possibly Huge Storm Midweek, and Fresh Snow From Utah to Telluride - OnTheSnowonthesnow.com
  4. 4Weather Update — November 11, 2026 — Eastside Weathereastsideweather.com
  5. 5Above 80 inches | Kalshi Prediction Market — Frenzy Capitalfrenzycap.com
  6. 6Mammoth Mountain snowfall total by December 24th… | Frenzy Capitalfrenzycap.com

4. Market Data

Contract Snapshot

This market resolves YES if the Mammoth Mountain snowfall total by December 24th, 12:00 am EST, is above 95 inches, and NO if it is 95 inches or less. The event's measurement cutoff is December 24th at 12:00 am EST, with the market beginning approximately 39 days prior. The maximum payout date for this market is December 24, 2026, and no specific data sources or settlement conditions are detailed on this page.

Available Contracts

Market options and current pricing

Outcome bucket Yes (price) No (price) Last trade probability
Above 140 inches $0.17 $0.90 98%
Above 35 inches $0.99 $0.08 92%
Above 50 inches $0.90 $0.16 82%
Above 65 inches $0.79 $0.29 79%
Above 80 inches $0.64 $0.44 63%
Above 95 inches $0.51 $0.56 50%
Above 110 inches $0.35 $0.73 35%
Above 125 inches $0.25 $0.84 24%
Above 165 inches $0.09 $0.94 9%
Above 190 inches $0.07 $0.98 0%
Above 215 inches $0.06 $0.99 0%

Market Discussion

Prediction markets show disagreement on Mammoth Mountain's snowfall total by December 24, 2026, with Kalshi odds for exceeding 140 inches at 13% as of Nov 14, 2026, contrasting sharply with OpinionKings' 99% for the same threshold as of Nov 12, 2026 [1][2][3]. While some forecasts predict a "Super El Niño" leading to above-average snowfall, including ~85 inches in December [4][5][6][7], the season's total was only 12 inches as of mid-November 2026 [8]. An AI agent analyzing historical data, including El Niño analogs, estimated a low ~10% probability of exceeding 165 inches by the resolution date [9].

Sources (9)
  1. 1Mammoth Mountain snowfall total by December 24th · OpinionKingsopinionkings.com
  2. 2Mammoth Mountain snowfall total by December 24th Odds | Kalshipredictmarketcap.com
  3. 3Mammoth Mountain snowfall total by December 24th — Live Oddspredictionmarkets.us
  4. 4Mammoth Mountain Weather Forecast & Discussion - 93546mammothsnowman.com
  5. 52026-2027 Winter Forecastyoutube.com
  6. 6OpenSnow prédit un hiver record « Super El Niño » avec un potentiel massif de poudreuse dans le sud-ouest et un risque de températures élevées - Skinordique.netskinordique.net
  7. 7Skiers Predict Which Mountains Will Get the Deepest Powder This El Niño Season - Unofficial Networksunofficialnetworks.com
  8. 8Snowfall History | Mammoth Mountainmammothmountain.com
  9. 9Scan: Above 165 inches — Forecasting Agentforecast.agenticlearning.ai

5. Trust Index

Octagon Trust Index Kalshi 67 Caution

Order book is critically thin.

Primary risk· Trade quality

How it adds up
Integrity80% of score77Good

Market integrity is low (63), but Integrity averages all three scores, so the other two pull it up. Only a critically low score would cap the total.

Trade quality20% of score28Avoid

Includes the cost to trade: a $1,000 order can't be filled here because the order book is too thin.

Trust score67Caution

Weighted blend with hard caps — a critically weak safety pillar, or a severe trading anomaly, caps the total regardless of the rest. Full methodology · About the Trust Index

Trust profile
Integrity4 screens run · 6 don't apply
Market integrity
63Caution

Outcome can be influenced

Thin-volume movesTrade signals · high confidence

“Above 50 inches” made a sharp jump with almost no trading behind it.

Large tradesTrade signals · medium confidence

Largest single print on KXMAMMOTHSNOW-24DEC26-GT95 carried 47% of its $569 tape (window is 100% of 24h flow; print is 22d old)

Screened clean
Size patternsNo distribution read Clear
2 screens not run
Outcome control · doesn't apply to this market type
Thin-leg conviction · doesn't apply to this market type
Info fairness
80Good

Structural prior — no screens apply

No suspicious activity on any screen

Screened clean
Information exposureNo concentrated group can know the outcome materially early. Clear
4 screens not run
Move vs. catalyst · doesn't apply to this market type
Longshot repricing · doesn't apply to this market type
Pre-broadcast certainty · doesn't apply to this market type
Cross-venue timing · doesn't apply to this market type
Resolution quality
92Strong

Resolution mechanism is dependable

No suspicious activity on any screen

Resolution rules read: Clear

Liquidity
34Very thin

Hard to fill near the screen price

8 contracts · worst first · 3 below the volume floor — not scored

Above 50 inches26
Very thin · low confidence

Light recent trading — size may not fill near the screen price.

Above 165 inches26
Very thin · low confidence

Light recent trading — size may not fill near the screen price.

Above 125 inches28
Very thin · low confidence

Light recent trading — size may not fill near the screen price.

Above 35 inches30
Very thin · low confidence

Light recent trading — size may not fill near the screen price.

Above 110 inches40
Thin · low confidence

Light recent trading — size may not fill near the screen price.

Above 95 inches46
Thin · low confidence

Light recent trading — size may not fill near the screen price.

Above 80 inches49
Thin · low confidence

Light recent trading — size may not fill near the screen price.

Above 140 inches—
No recent trading to measure

No recent trading to measure

Move quality
70Stable

No significant moves

8 contracts · worst first · 3 below the volume floor — not scored

Above 140 inches—
Only 0 candle closes

Only 0 candle closes

Above 35 inches—
No trading in 26h

No trades in the last 26h — nothing to confirm

Above 50 inches—
No trading in 5d

No trades in the last 5d — nothing to confirm

Above 80 inches—
No trading in 2d

No trades in the last 2d — nothing to confirm

Above 95 inches—
No trading in 2d

No trades in the last 2d — nothing to confirm

Above 110 inches—
No trading in 2d

No trades in the last 2d — nothing to confirm

Above 125 inches—
No trading in 2d

No trades in the last 2d — nothing to confirm

Above 165 inches—
No trading in 2d

No trades in the last 2d — nothing to confirm

Rule clarity
100Clear

Counts toward Resolution quality, not here

8 contracts · worst first · 3 below the volume floor — not scored

Above 140 inches100
Clear · high confidence

All checks pass

objective outcome · Clearofficial source · Cleartime boundary · Clear
Above 35 inches100
Clear · high confidence

All checks pass

objective outcome · Clearofficial source · Cleartime boundary · Clear
Above 50 inches100
Clear · high confidence

All checks pass

objective outcome · Clearofficial source · Cleartime boundary · Clear
Above 80 inches100
Clear · high confidence

All checks pass

objective outcome · Clearofficial source · Cleartime boundary · Clear
Above 95 inches100
Clear · high confidence

All checks pass

objective outcome · Clearofficial source · Cleartime boundary · Clear
Above 110 inches100
Clear · high confidence

All checks pass

objective outcome · Clearofficial source · Cleartime boundary · Clear
Above 125 inches100
Clear · high confidence

All checks pass

objective outcome · Clearofficial source · Cleartime boundary · Clear
Above 165 inches100
Clear · high confidence

All checks pass

objective outcome · Clearofficial source · Cleartime boundary · Clear
Trade quality
28Avoid

Order book is critically thin

Thin market — entering or exiting at fair value will be difficult.

Outcome quality 35 (notional-weighted across 7 scored legs)

$100 order: 4.0c slippage (~5% of a 87c contract)

$1,000 order: book too thin to fill

$10,000 order: book too thin to fill

3 below the volume floor — not scored

Above 140 inches–Market scoreLiquidity–Move quality–Rule clarity100
Why this score
Liquidity
No recent trading to measure

No recent trading to measure

Move quality
Only 0 candle closes

Only 0 candle closes

Rule clarity
100 · Clear · high confidence

All checks pass

objective outcome · Clearofficial source · Cleartime boundary · Clear
Above 35 inches30Market scoreLiquidity30Move quality–Rule clarity100
Why 30
Liquidity
30 · Very thin · low confidence

Light recent trading — size may not fill near the screen price.

Move quality
No trading in 26h

No trades in the last 26h — nothing to confirm

Rule clarity
100 · Clear · high confidence

All checks pass

objective outcome · Clearofficial source · Cleartime boundary · Clear
Above 50 inchesPrimary26Market scoreLiquidity26Move quality–Rule clarity100
Why 26
Liquidity
26 · Very thin · low confidence

Light recent trading — size may not fill near the screen price.

Move quality
No trading in 5d

No trades in the last 5d — nothing to confirm

Rule clarity
100 · Clear · high confidence

All checks pass

objective outcome · Clearofficial source · Cleartime boundary · Clear
Above 80 inches49Market scoreLiquidity49Move quality–Rule clarity100
Why 49
Liquidity
49 · Thin · low confidence

Light recent trading — size may not fill near the screen price.

Move quality
No trading in 2d

No trades in the last 2d — nothing to confirm

Rule clarity
100 · Clear · high confidence

All checks pass

objective outcome · Clearofficial source · Cleartime boundary · Clear
Above 95 inches46Market scoreLiquidity46Move quality–Rule clarity100
Why 46
Liquidity
46 · Thin · low confidence

Light recent trading — size may not fill near the screen price.

Move quality
No trading in 2d

No trades in the last 2d — nothing to confirm

Rule clarity
100 · Clear · high confidence

All checks pass

objective outcome · Clearofficial source · Cleartime boundary · Clear
Above 110 inches40Market scoreLiquidity40Move quality–Rule clarity100
Why 40
Liquidity
40 · Thin · low confidence

Light recent trading — size may not fill near the screen price.

Move quality
No trading in 2d

No trades in the last 2d — nothing to confirm

Rule clarity
100 · Clear · high confidence

All checks pass

objective outcome · Clearofficial source · Cleartime boundary · Clear
Above 125 inches28Market scoreLiquidity28Move quality–Rule clarity100
Why 28
Liquidity
28 · Very thin · low confidence

Light recent trading — size may not fill near the screen price.

Move quality
No trading in 2d

No trades in the last 2d — nothing to confirm

Rule clarity
100 · Clear · high confidence

All checks pass

objective outcome · Clearofficial source · Cleartime boundary · Clear
Above 165 inches26Market scoreLiquidity26Move quality–Rule clarity100
Why 26
Liquidity
26 · Very thin · low confidence

Light recent trading — size may not fill near the screen price.

Move quality
No trading in 2d

No trades in the last 2d — nothing to confirm

Rule clarity
100 · Clear · high confidence

All checks pass

objective outcome · Clearofficial source · Cleartime boundary · Clear

underwriting_v1.4 · computed Nov 14, 2026

6. In historical seasons where Mammoth Mountain's mid-November snowpack was more than 25% below average, how often did snowfall recover to meet the ~67-inch December average by Christmas Eve?

Probability of 65-inch snowfall by Dec 24 (2026)~75% [1][2][3]
Market-implied median total by Dec 24 (2026)~91.5 inches [1][2][3]
Historical December average snowfall~67 inches [1][2][3]
Historical data does not directly support the specific snowfall recovery analysis. No historical records were available that paired Mammoth Mountain's mid-November snowpack, expressed as a percentage of average, with December 24th seasonal totals [4][1][2]. Consequently, it was not possible to directly calculate the base rate for seasons where mid-November snowpack was over 25% below average and subsequently recovered to meet the approximate 67-inch December average by Christmas Eve [4][1][2].
Market data offers insights into Mammoth Mountain's 2026 snowfall probabilities. The Kalshi market for 'Mammoth Mountain snowfall total by December 24th' (KXMAMMOTHSNOW-24DEC26) provides projections for the 2026 season [1][2][3]. As of November 14, 2026, the 65-inch snowfall threshold on this market is priced at approximately 75% [1][2][3]. This suggests a market-implied probability of about 75% that Mammoth Mountain will achieve or surpass the approximate 67-inch December average by Christmas Eve [1][2][3]. Moreover, the market's implied median total snowfall for the 2026 season is estimated at roughly 91.5 inches, substantially exceeding the historical approximate 67-inch December average mentioned in the query [1][2][3].
Sources (4)
  1. 1Mammoth Mountain snowfall total by December 24th | PredictPediapredictpedia.com
  2. 2Mammoth Mountain snowfall total by December 24th… | Frenzy Capitalfrenzycap.com
  3. 3Mammoth Mountain snowfall total by December 24th Odds | Kalshipredictmarketcap.com
  4. 4Mammoth Mountain snowfall total by December 24th Odds & Predictionskalshi.com

7. What are the aggregate snowfall projections from OpenSnow's forecasted storms for Mammoth Mountain through Thanksgiving week 2026?

Snowfall projection through Thanksgiving week45 inches (OpenSnow, as of Nov 13-14, 2026) [1]
Broader 15-day forecasted snowfall64 inches (OpenSnow, as of Nov 13-14, 2026) [1]
Snowfall in prior 11-15 days12 inches (OpenSnow, as of Nov 13, 2026) [1]
OpenSnow forecasts significant snowfall for Mammoth Mountain through Thanksgiving. OpenSnow projected a total of 45 inches of snowfall for Mammoth Mountain through Thanksgiving week 2026, based on an update around November 13–14, 2026 [1]. This projection specified 19 inches forecasted for November 14–18 and an additional 26 inches for Thanksgiving week, covering November 19–23 [1]. A broader 15-day forecast, updated concurrently, indicated an overall total of 64 inches of snowfall for Mammoth Mountain, which included 19 inches projected for November 24–28 [1]. Mike Korotkin, an OpenSnow local expert, identified three distinct storms impacting this period: Storm #1 on November 13, Storm #2 from November 16 through Tuesday, and Storm #3 on November 18–19, noting a possibility of more active weather during Thanksgiving week [1].
Recent snowfall reports accompany the long-term projections. OpenSnow reported 12 inches of snowfall in the 11–15 days prior to November 13, 2026 [1]. As of Friday, November 13, at 6:35 AM, OpenSnow indicated no new snow in the preceding 24 hours [1]. It is important to note that for the Kalshi 'Mammoth Mountain snowfall total by December 24th' market, the final resolution depends on the official Main Lodge Season Total, and forecasts or projections do not explicitly contribute to this resolution [2][3].
Sources (3)
  1. 1Mammoth Mountain Snow Forecast | OpenSnowopensnow.com
  2. 2Mammoth Mountain snowfall total by December 24th | PredictPediapredictpedia.com
  3. 3Mammoth Mountain snowfall total by December 24th · OpinionKingsopinionkings.com

8. How do the underlying data sources of the Kalshi market and OpinionKings' forecast explain their differing snowfall projections for Mammoth by December 24, 2026?

Kalshi Snowfall Median~91.5 inches (odds above 140 inches: 13%) [1][2][3]
OpinionKings Snowfall >140in99% probability [1][2][3]
Kalshi Market Volume$13,158–$13,352 [2][4][1]
Kalshi and OpinionKings project significantly different Mammoth snowfall totals by December 24, 2026. Kalshi traders anticipate a market median of approximately 91.5 inches, with only a 13% probability of total snowfall exceeding 140 inches. In stark contrast, OpinionKings traders assign a 99% likelihood that snowfall during the October 1–December 24 period will surpass 140 inches [3][1][2]. This substantial discrepancy arises primarily from their distinct resolution data sources, along with differences in trader composition and market liquidity.
Resolution data sources primarily explain the diverging snowfall projections for Mammoth Mountain. Kalshi's market contracts are resolved based on the official 'Main Lodge Season Total' reported at the Main Lodge location, covering October 1 to December 24, 2026 [3][5]. OpinionKings, conversely, relies on multiple data sources for resolution, including OnTheSnow, The Wall Street Journal, and the Alterra Mountain Company, rather than a single specific resort report [1]. The high probability from OpinionKings suggests that its traders are anchoring their forecasts to potentially higher seasonal figures reported by these alternative sources. Despite both platforms employing identical measurement windows (October 1 to December 24, 2026, with a 4:00 PM ET reading) and excluding all forecasts, this projection gap persists [3][1][2].
Market liquidity and trader characteristics further contribute to projection differences. Kalshi's market exhibits limited trading activity, with a total volume of approximately $13,158–$13,352 and roughly $3,033 in liquidity [2][4][1]. This lower activity suggests a potentially smaller trader base, possibly driven more by weather models. The variations in authoritative recorded seasonal totals, combined with these differences in trader composition and liquidity, are key factors in explaining the diverging snowfall outlooks between the two platforms [3][1][2].
Sources (5)
  1. 1Mammoth Mountain snowfall total by December 24th · OpinionKingsopinionkings.com
  2. 2Mammoth Mountain snowfall total by December 24th… | Frenzy Capitalfrenzycap.com
  3. 3Mammoth Mountain snowfall total by December 24th | PredictPediapredictpedia.com
  4. 4Mammoth Mountain snowfall total by December 24th Odds | Kalshipredictmarketcap.com
  5. 5Mammoth Mountain snowfall total by December 24th Odds & Predictionskalshi.com

9. What are the official sources for historical daily and cumulative snowfall data for Mammoth Mountain's Main Lodge, as used for the Kalshi market's resolution?

Official Data SourcesOnTheSnow.com, Wall Street Journal, Alterra Mountain Company [1]
Resolution MetricMain Lodge Season Total in inches [2][3]
Measurement PeriodOctober 1, 2026, to December 24, 2026 [2][4][3]
For the resolution of Kalshi markets concerning Mammoth Mountain's Main Lodge snowfall totals, the official sources utilized are OnTheSnow.com's Mammoth Mountain snow report, The Wall Street Journal's snowfall tracking, and Alterra Mountain Company's official Mammoth Mountain Mountain Report. These sources collectively provide the 'Main Lodge Season Total' for market resolution [1].
The market's final value is determined by the total snowfall recorded at Mammoth Mountain from October 1, 2026, through December 24, 2026 [2][4][3]. The precise measurement recorded at 4:00 PM ET on December 24, 2026, will be used [2][4][3]. The specified metric is the 'Main Lodge Season Total' in inches, explicitly excluding measurements from McCoy Station, The Summit, base depth, or 24/48/72-hour totals [2][3]. Kalshi states that it maintains no affiliation with the Alterra Mountain Company, which manages the resort and publishes its official Mountain Report [2][5].
Sources (5)
  1. 1Mammoth Mountain snowfall total by December 24th · OpinionKingsopinionkings.com
  2. 2Mammoth Mountain snowfall total by December 24th | PredictPediapredictpedia.com
  3. 3Mammoth Mountain snowfall total by December 24th odds: Above 140 inches 98% on Kalshipredictdesks.com
  4. 4Mammoth Mountain snowfall total by December 24th Odds & Predictionskalshi.com
  5. 5Mammoth Mountain snowfall total by December 24th Odds | Kalshipredictmarketcap.com

10. How did Mammoth Mountain's early-season snowfall (Oct 1–Dec 24) perform relative to average during previous strong El Niño winters like 1997-98 and 2015-16?

Historical comparisons to past strong El Niño winters are not possible. The available facts do not contain historical snowfall data for Mammoth Mountain during previous strong El Niño winters like 1997-98 and 2015-16, nor do they define average snowfall for the October 1 to December 24 period. Consequently, a direct quantitative comparison of early-season snowfall performance against these specific past winters cannot be made using the provided information.
Current market analysis predicts a solid early season for 2026. The Kalshi market titled 'Mammoth Mountain snowfall total by December 24th' resolves based on the Main Lodge Season Total (inches) recorded between October 1 and December 24, 2026 [1][2]. As of November 14, 2026, the market's implied median snowfall stands at approximately 91.5 inches, with 50/50 odds situated near the 'Above 95 inches' threshold [3]. The odds ladder on this date indicates that traders anticipate a solid but not record-breaking early season, which is generally consistent with a normal-to-slightly-above-average El Niño-influenced winter [4].
Sources (4)
  1. 1Mammoth Mountain snowfall total by December 24th | PredictPediapredictpedia.com
  2. 2Mammoth Mountain snowfall total by December 24th · OpinionKingsopinionkings.com
  3. 3Mammoth Mountain snowfall total by December 24th Odds | Kalshipredictmarketcap.com
  4. 4Mammoth Mountain snowfall total by December 24th… | Frenzy Capitalfrenzycap.com

11. What Could Change the Odds

Key Catalysts

Mammoth Mountain opened its 2026-27 season early on November 5, 2026, driven by an early El Niño storm [1][2]. The 2026-27 season total is 12" (3" Oct + 9" Nov) as of Nov 13 [3]. A Nov 13 storm delivered 9-10" at Main Lodge, with 10-12" more forecast for Nov 14, 2026 [4]. SnowStash forecast up to 33" falling Nov 12-14 [1]. Mammothsnowman's Nov 13 forecast anticipates 45-55" more snow for the month [4]. This winter features a potentially record 'super El Niño' with forecast SST anomalies of 3.5-4.5°C [5][6]. NOAA gave >90% chance of a very strong El Niño in September 2026, and NWS cited a 69% chance of a historic event exceeding all El Niños since 1950 for Oct-Dec [6][7]. The ECM EPS 45-day forecast shows above-normal precipitation for Mammoth with ~85" of December snowfall; the CFS model agrees on above-normal West Coast precipitation [4].
Key upcoming storm series include Nov 16-20, with 4-5" on Monday, 8-12" on Thursday Nov 19, and 1-2" on Friday [4]. A possible major trough is indicated for Nov 22-24 per GEFS, with MJO reactivation potentially occurring in early December [4][5]. The Kalshi 'Mammoth Mountain snowfall total by December 24th' market prices 99% for above 95", 96% for above 110", and 89% for above 125" [8]. OpinionKings showed 99% probability of above 140" as of Nov 12, 2026 [9]. The market resolves on December 24, 2026, at 12:00am EST [8].
Bearish factors include a record-early stratospheric sudden warming (SSW) event, whose tropospheric effects may emerge 3-4 weeks later (late Nov/early Dec), potentially disrupting the storm track [4][2]. Model spread is wide, with GFS showing ~5" liquid versus ECM's ~0.75" for the week after Nov 13 [4]. El Niño storms can bring warm, wet 'Sierra cement' snow, which may limit lower-elevation accumulation [4]. OpenSnow's seasonal forecast indicates heaviest Sierra storm cycles will ramp up after the new year [10]. Historically, only a handful of seasons exceeded 165" by the end of December, and the Dec 24 cutoff trims full-December figures [3][6].

Key Dates & Catalysts

  • Strike Date: December 24, 2026
  • Expiration: December 31, 2026
  • Closes: December 24, 2026
Sources (10)
  1. 1Mammoth Mountain Opens Early on November 5, More Snow Duesnowstash.com
  2. 2Snowstorm helps California's Mammoth Mountain open ski season earlyweather.com
  3. 3Snowfall History | Mammoth Mountainmammothmountain.com
  4. 4Mammoth Mountain Weather Forecast & Discussion - 93546mammothsnowman.com
  5. 52026-2027 Winter Forecastyoutube.com
  6. 6Scan: Above 165 inches — Forecasting Agentforecast.agenticlearning.ai
  7. 7Will El Niño snowfall allow Tahoe ski resorts to open early?tahoeskiworld.com
  8. 8Mammoth Mountain snowfall total by December 24th Odds & Predictionskalshi.com
  9. 9Mammoth Mountain snowfall total by December 24th · OpinionKingsopinionkings.com
  10. 10Super El Niño odds for California snow fall revealed in new expert map: ‘Record-breaking’ – newsconexion.comnewsconexion.com