How It Works:

The PowDay
Algorithms.

This is how we turn large datasets into one number. We analyze the quality of the snow itself, how well it has been preserved, and how enjoyable it will be to ski or ride.

Mountain peak in bright light

The PowScore

For forecasting classic powder days based on new snowfall.

Base Snow Quality
  • Freshness: More recent snowfall scores higher, with value decaying over time.
  • Dryness (SLR): The Snow-to-Liquid Ratio determines if it's "blower" powder or "Sierra cement."
  • Depth: More new snow is better, with diminishing returns after a certain point.
Snowpack Preservation
  • Post-Storm Temps: Consistently cold temperatures since the snowfall preserve quality.
  • Wind Scour: High winds can strip the surface or create wind-pressed "slabs," reducing quality.
  • Sun Crust: Solar radiation and warm spells create breakable crusts that heavily penalize the score.
Base & Surface
  • Base Depth: A deep, established snowpack provides better coverage and a more resilient surface.
  • Rain Damage: Any rain since the snowfall is highly detrimental and is heavily penalized.
  • Melt-Freeze: Significant melting and refreezing creates a hard floor, negatively impacting the feel.
Enjoyment Rating

This parallel 1-10 rating asks 'Is it worth it?' It balances snow quality with weather comfort, acknowledging that great snow often trumps bad weather.

  • PowScore (Snow Quality)75%
  • Weather Comfort25%
PowScore Weighting
A weighted geometric mean heavily prioritizing the quality of the snow itself.
  • Base Snow Quality
  • Snowpack Preservation
  • Base Depth & Surface

The Spring 'Corn' Score

For forecasting perfect "corn" snow—the holy grail of spring skiing.

Spring Score Weighting
Highest importance is placed on a solid overnight refreeze to lock in the cycle.
  • Overnight Refreeze
  • Daytime Transition
  • Snowpack Longevity
  • The Corn Window
Overnight Refreeze
  • Overnight Low: Ideal refreeze occurs when temps drop well below freezing.
  • Cloud Cover: Clear nights allow radiant cooling, creating a firmer snowpack.
  • Dew Point: Low dew points help the snow surface dry out and freeze solid.
Daytime Transition
  • Afternoon High: Temps must rise enough to soften the frozen surface, but not so much it turns to slush.
  • Sunlight: Strong sun is crucial for efficiently transitioning the snow to a 'corny' texture.
  • Wind: High winds can accelerate melting or keep the surface frozen, disrupting the cycle.
The Corn Window
  • Timing & Duration: We estimate when the corn will be perfect and for how long. A longer window scores higher.
  • No-Freeze Penalty: If the snowpack doesn't freeze overnight, a true corn cycle is impossible.
Snowpack Longevity
  • Overall Depth: A deep snowpack is more resilient to warm temps and provides better coverage.
  • Melt Rate: We analyze the forecast to determine how quickly the snowpack is shrinking.
  • Hard Floor: A penalty is applied if the base is too thin to support the cycle.
Important Disclaimer
This is a forecast, not a guarantee.

Our scores are sophisticated estimates based on cutting-edge weather modeling. However, mountain weather is notoriously unpredictable and microclimates can create variable conditions across a single resort. Always ski or ride with caution, be aware of your surroundings, and respect all mountain safety guidelines.