wind · United States
Boulder, Colorado
December–January peak downslope gust
Modelled demonstration series · not observed data
The dangerous combination on the Front Range is a dry, snowless winter and a downslope windstorm on the same day — grass fires driven at highway speed through suburbs. This is a wind chart that should be read next to the snowpack charts on this wall, because neither of them is frightening alone.
75 years, modelled
Same reading, two normals
| Normal | Mean | σ | Pct | Return |
|---|---|---|---|---|
| 1951–1980 | 130 km/h | +3.60σ | 99.984th | 1 in 6,300 years |
| 1991–2020 | 153 km/h | +2.31σ | 99th | 1 in 95 years |
Today would be the highest value in the entire 75-year modelled series. Past the series' standing high of 183 km/h (1989). Nothing about the reading changes between rows — only the yardstick.
The season here
Chinook winds pour down the Front Range in winter, warming and drying as they descend. They are strongest when the mountain snowpack is thin.
Where this series comes from
MODELLED SERIES — not observed. Parameters set from published Front Range downslope windstorm climatology. The 75 annual values are synthesised by the seeded generator.
Every number on this page comes from a modelled series: 75 annual values synthesised by a seeded generator from published climatological parameters for Boulder, Colorado. It shows how anomaly reasoning works. It is not a measurement and must not be cited as one.
How to read σ
σ counts standard deviations from this place's own normal. The sigma guide · return periods.
More wind stations
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