SNOWD

Avalanche Knowledge & SNOWD Data Guide

Learn how to read avalanche forecasts, understand danger ratings and roses, and interpret how SNOWD displays snow and forecast data.

Avalanche information in SNOWD is for awareness and routing to official forecasts. Always use the official avalanche center forecast for your zone and terrain before traveling in avalanche terrain.

Avalanche Forecast Education

Utah Avalanche Center (UAC)

Avalanche Danger Scale

Utah Avalanche Center overview explaining avalanche danger ratings and how to interpret the scale.

Utah Avalanche Center (UAC)

How to Read an Avalanche Forecast

UAC tutorial for understanding forecast structure, avalanche problems, and travel advice.

Utah Avalanche Center (UAC)

Danger Rose and Location Rose Tutorial

UAC tutorial explaining the danger rose and location rose used in avalanche forecasts.

How To Read SNOWD Avalanche & Snow Context

Station Data vs Avalanche Forecasts

SNOWD combines point measurements with regional avalanche information. They answer different questions.

  • SNOTEL and weather stations are point observations at one location and elevation.
  • Avalanche danger ratings are regional forecasts that vary by elevation band, aspect, and terrain.
  • A station near your objective can be useful context, but it is not a substitute for the avalanche forecast for your terrain.

Why SNOWD Sometimes Shows Nearby Avalanche Regions

Some stations are outside an official avalanche forecast region.

  • When a station is outside a forecast area, SNOWD shows nearby forecast regions to give you context.
  • Nearby regions help you find the right avalanche center and forecast page quickly.
  • Do not assume nearby region danger ratings directly apply to your location without checking the official forecast area boundaries and terrain details.

How To Interpret SNOWD Snowfall Data

Station Snowfall: How To Interpret Derived Daily Snow

SNOWD shows a consistent station-based snowfall estimate, which may differ from ski area reported snowfall totals.

  • SNOWD estimates daily snowfall from positive day-to-day changes in station snow depth.
  • Stations measure conditions at a single point, so wind loading/scouring, settlement, and melt can make station-derived snowfall differ from what skiers experience across a slope or resort.
  • Negative day-to-day snow depth changes are treated as 0 inches of new snow (not negative snowfall).
  • Use SNOWD station snowfall as a consistent trend/comparison signal across days and storms, not as an exact on-slope storm total.
  • Snow depth and snow water equivalent may not move together the same way in every storm because snow density changes.

Forecast Snowfall: Calendar Days vs Ski Days

SNOWD forecast snowfall is grouped into local calendar-day totals, which can differ from overnight ski-day expectations.

  • Forecast snowfall is summed into local calendar-day totals, not ski-area overnight reporting windows.
  • A storm that starts late in the evening and continues overnight may be split across two dates in SNOWD.
  • Resort reports often emphasize overnight or 24-hour totals, which may not match calendar-day totals shown in SNOWD.
  • Morning ski conditions can reflect snow that fell the previous calendar day plus overnight accumulation and wind transport.
  • Probability of precipitation (PoP) is the highest probability shown within that day's forecast periods, not a guarantee of the displayed snowfall total.
  • Forecast confidence generally drops beyond about 3 days, especially for snowfall timing and exact amounts.