Snow Briefing · Mountain pass
Santiam Pass, OR
Mountain pass • US-20 • 4,842 ft • NBM 18Z 15 Nov 2026 • issued 19:39Z
The blend has 1.3″ of snow for Santiam Pass over the next three days, 0.5″ of it in the first 24 hours, and 5.9″ over its ten days. Verdict: shovel it.
The next ten days
Plow verdict on the 72-hour total: Shovel it
| Horizon | Snow | Range 10–90% | Ice | Chance ≥1″ | Chance ≥6″ |
|---|---|---|---|---|---|
| Next 24 h | 0.5″ | 0.0–1.6″ | 0.00″ | 18% | 0% |
| Next 48 h | 0.7″ | 0.0–2.0″ | 0.00″ | 22% | 0% |
| Next 72 h | 1.3″ | — | 0.00″ | — | — |
| 5 days | 1.8″ | — | — | — | — |
| 7 days | 3.7″ | — | — | — | — |
| 10 days | 5.9″ | — | — | — | — |
Snow is the blend's deterministic forecast; the range is its 10th to 90th percentile and the chances are its own exceedance probabilities. Ice is freezing-rain accretion.
Day by day
| Climate day (12Z–12Z) | Snow | 90th pct | Chance ≥1″ | Chance ≥6″ |
|---|---|---|---|---|
| Tue 17 Nov | 0.2″ | 0.5″ | 0% | 0% |
| Wed 18 Nov | 0.4″ | — | — | — |
| Thu 19 Nov | 0.7″ | — | — | — |
| Fri 20 Nov | 0.1″ | — | — | — |
| Sat 21 Nov | 0.5″ | — | — | — |
| Sun 22 Nov | 1.2″ | — | — | — |
| Mon 23 Nov | 0.7″ | — | — | — |
| Tue 24 Nov | 0.3″ | — | — | — |
| Wed 25 Nov | 1.3″ | — | — | — |
Climate days run 12Z to 12Z, the window the NWS national snowfall analysis scores. Percentiles and chances are available for the first two days.
Two weeks out · ECMWF ensemble
| By | p10 | Median | p90 | Members ≥1″ | Members ≥6″ |
|---|---|---|---|---|---|
| Day 3 | 0.2″ | 0.5″ | 1.1″ | 24% | 0% |
| Day 5 | 2.7″ | 3.9″ | 6.7″ | 100% | 16% |
| Day 7 | 3.3″ | 5.1″ | 8.2″ | 100% | 36% |
| Day 10 | 5.1″ | 7.3″ | 11.4″ | 100% | 78% |
| Day 15 | 8.4″ | 16.5″ | 27.4″ | 100% | 94% |
ECMWF open data, 50 perturbed members at 0.25°, snow at a fixed 10:1 ratio, run 00Z 15 Nov. Cumulative from the run.
Density, level and trend
| Density at 48 h | 6.6 lb/ft³ |
| Load at 48 h | 0.4 lb/ft² |
| Snow-to-liquid ratio at 48 h | 9:1 |
| Snow level at 24 h / 48 h | — / — |
| Freezing rain chance, 48 h | 0% |
| Trend | down 0.2″ vs the previous run (48 h) |
How good is this forecast?
The blend's day-1 snowfall this season, scored against the NWS national snowfall analysis: mean absolute error 1.12″, bias −0.21″, critical success index at 6″ 0.06 over 71 scored days. Last scored day: 14 Nov 2026.
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forecastflakes.com/products/santiam-pass-or-pass · NWS National Blend of Models · ECMWF open data · © 2026 Forecast Flakes · not an official warning source