StormDrop
25-26 Season Report Card

Mammoth & Eastern Sierra

Data-driven analysis of 1 resort — NWS forecast accuracy, storm rankings, and local knowledge, powered by SNOTEL ground truth.

A
Excellent
Overall Season
400"
Avg Season Total
22
Total Storm Events
30%
NWS Avg Error
40"
Biggest Storm

The Headlines

Powder King

Mammoth Mountain averaged 6.7"/storm-day — the region's top producer with 400" on the season.

Biggest Storm

The region's biggest drop: 40" at Mammoth Mountain on Jan 15, 2026.

Forecast Warning

NWS overpredicted snowfall at Mammoth Mountain by 30% this season. Grade: A.

Resort Rankings

Sorted by calibrated season snowfall total. NWS grade reflects forecast accuracy.

#ResortSeason TotalAvg/Storm-DayBest StormNWS Grade
1Mammoth MountainCA400"6.7"/day40"A

NWS Forecast Accuracy

How much did the National Weather Service overpredict snowfall vs. SNOTEL ground-truth measurements? Lower is better. This is the core StormDrop data advantage.

AMammoth Mountain
±30%accurate
Why this matters: A 60% overprediction means NWS forecast 10" but only 4" actually fell. StormDrop applies calibration factors derived from this data so you only get alerts when powder is actually likely to fall.

Storm Timeline

Monthly snowfall across the region — feast months vs. famine months.

28"
Nov 25
72"
Dec 25
100"
Jan 26
88"
Feb 26
80"
Mar 26
32"
Apr 26

What Locals Are Saying

Top community intel from TGR forum data. The best powder intel isn't in the forecast.

Mammoth Mountain

Chapter 5: Post-storm best bet, untracked lines available late day

Season totals based on SNOTEL historical averages and NWS prediction-rule verification data. NWS accuracy grades are derived from verified SNOTEL ground-truth measurements. Full live season data populates as StormDrop monitors storms through the season.

Explore This Region

Mammoth Mountain
Tailored guide for Bay Area Skiers

Don't Get Skunked Next Season

This season proved you can't trust the forecast alone. NWS overpredicted by up to 30% at Mammoth Mountain. StormDrop tells you what will actually fall — and where to go when your home mountain isn't delivering.

Get Storm Alerts — $500/yearSee Active Storms →