What Does "% of Normal" Mean?
When you see a report stating that a mountain basin is at "115% of Normal," what does that actually measure?
Federal agencies like NOAA and NRCS calculate 30-year official climate normals (currently using the 1991–2020 baseline period). The median snowpack for every calendar day is derived from this 30-year record.
Median vs. Average (Mean)
In snowpack analysis, NRCS uses the median rather than the average. Because extreme high-snow winters can skew the mathematical average, the median represents the true middle 50th-percentile benchmark.
Season Trajectory
Tracking the percent of normal allows riders and hydrologists to determine whether the season is pacing ahead or behind historic norms, giving an early indicator of spring riding longevity.