Big fires are burning close by, but almost all of the acreage is on the far side of Mt Hood, and the ocean air that pushes up your valley on most late-August days keeps their smoke heading the other way — that's why the monitor 9 miles from the house is reading clean right now with 72,000 acres burning 17 miles east. Our best guess for the worst single day of your weekend is around 30, which most people would not notice, and there's roughly a 6-in-10 chance all three days stay in the Good range.
The real risk is the roughly 1-in-6 chance the wind flips to easterly in the last week of August and pours smoke over the pass into your valley for a day or two, and you would see that coming about four days ahead in the Government Camp forecast.
If we ran this weekend 100 times, here is how they would split. Hover a row to pick it out of the dots.
| 5 in 1055% | Clear weekend AQI 0-50 Blue sky, maybe a faint brown smudge low on the eastern horizon over the pass in the afternoon. Windows open, kids outside all day, nobody mentions it. | nothing |
| 3 in 1025% | Hazy but fine AQI 50-100 Milky white sky, Mt Hood soft-edged or invisible, a campfire smell in the morning that burns off by noon. Sunsets are orange. Healthy adults are fine; one asthmatic friend takes it easy on the hike. | Run a purifier in the main room, close windows overnight and in the early morning, move the long hike to the afternoon or to the west side toward Sandy. |
| 1 in 1011% | One smoky day AQI 100-150 Visibility down to a few miles, sun a dull orange disc, throat scratch and headaches by afternoon, smoke smell indoors. Kids and anyone with asthma should stay in. | Indoor day: purifiers on high, windows shut, N95s for anyone going outside, cancel the hike, drive down to Sandy or Portland for the day if the valley is worse than the lowlands. |
| 1 in 109% | Real smoke episode AQI 150+ Brown-gray air you can taste, sun barely visible, ash flecks possible, headaches and coughing for most of the group, indoor air noticeably hazy even with windows shut. Possible Level 1 evacuation notice for the corridor. | Leave, or never come up. Twelve people in a smoke-filled valley house is a miserable weekend and a genuine health problem for anyone with asthma, heart issues, or a small child. |
The long-range ensembles show less east-wind risk than a normal year — weak evidence, but pointing the right way.
Caveat: this counts days whose dominant wind is easterly, which at a valley site also picks up ordinary overnight down-valley drainage, not only the Gorge-outflow events that actually carry smoke. Forecast and base rate are measured the same way, so the gap is the meaningful part; the absolute percentages are not a chance-of-smoke.
It is not one cut-off. Five sources arrive on five different dates, and the darker the strip, the more of them cover your weekend. Hover any day for the count.
= Since 2026-08-10 the forecast has moved steady (-4 on the likely worst day) across 2 daily updates. Shading above shows source coverage, not this movement - hover a past day to see what we said that morning.
| now | Fire size & containment how big the fires are and whether they are being held |
| now | Long-range ensembles (GEFS 0.5 + GEM) wind direction, 52 members · reaches 32 days out |
| Aug 15 | ECMWF ensemble (51 members) wind direction, the sharpest ensemble · reaches 13 days out |
| Aug 13 | Deterministic weather (16-day) day-by-day wind and temperature · reaches 15 days out |
| Aug 22 | Air-quality / smoke model (CAMS) actual AQI at the house · reaches 6 days out |
The controlling fact is geometry plus flow, not acreage: Grasshopper's 72,476 acres sit 17 miles east, past the crest, and the default late-August pattern here is onshore westerly flow with a nightly marine push that ventilates the west slope and drives that smoke into the Columbia Basin. The evidence confirms this is working — 11 AQI at Multorpor right now, and a 30-day mean daily max of only 15, which means no day in the past month with these same fires burning came anywhere near 100. But I am not just restating climatology, because three things genuinely raise the risk: the season anomaly is 1.46, a 72k-acre fire at 23% containment on Aug 11 will still be producing smoke on Aug 28 (Oregon fires this size routinely persist past Labor Day, and the west-side season-ending rain median is mid-to-late September), and — the part that terrain does not protect against — AUSTIN at 719 acres and 0% containment, MITCHELL, and THE NARROWS are all 12-20 miles south and southwest, on the house's own side of the crest, where a south wind needs no mountain-crossing to smoke the valley. The bad path is a late-August ridge that kills the marine push and turns the gradient offshore: east flow spills Grasshopper's plume over Barlow Pass, and the house at 1,200 ft in the Salmon/Sandy drainage pools it under an overnight inversion, which is exactly how this location produces its 100-180 days.
A normal late August here is Clear - median AQI 12 across the last 4 years. On these exact dates: 2025: 16 · 2024: 10 · 2023: 11 · 2022: 11.
We are forecasting a worst day of 38, 26 points above that base rate. That departure rests entirely on the reasoning above; judge it for yourself.
| 12.5 mi | Mitchell S | 16 acres |
| 14.0 mi | The Narrows SSW | 5 acres |
| 17.4 mi | Grasshopper E | 72,476 acres · 23% contained |
| 19.8 mi | Austin S | 719 acres · 0% contained |
| 34.0 mi | Thomas Creek WSW | size not yet reported |
| 39.0 mi | High Lava N | 1,167 acres · 0% contained |
| 45.5 mi | Bench SSE | 67,071 acres · 86% contained |
The biggest hole in this forecast: 1 of the nearby fires (Thomas Creek) have no size reported yet. Whether those are 300-acre creepers or 20,000-acre runners is most of the answer.
If the weekend is clean you carried masks for nothing. If it is not, this is the difference between a bad weekend and a ruined one.
| Sandy | 19.4 mi |
| Brightwood | 15.5 mi |
| Welches | 14.3 mi |
Distance from each point on the drive in to the nearest fire. TripCheck is the authority on closures.
Fire perimeters from NIFC, evacuation zones from Oregon OEM, weather and alerts from NWS, air quality from AirNow (Multorpor, 8.7 mi away). The forecast is judged by Claude Opus 5 on the live data above, sampled 5 times and pooled conservatively.
It is a judgement, never scored against an outcome. Nobody forecasts smoke this far out: NOAA's smoke model runs 48 hours and the EPA's air-quality forecast is for tomorrow. Two-to-six weeks ahead is what meteorologists call the predictability desert. Anyone giving you a number for the trip right now - us included - is giving you a base rate with a story attached.
AQI here means the highest 24-hour PM2.5 value touching a day, at the house, on the local monitor scale - the same thing your phone shows. The model's own restatement of the target: “I am forecasting the US AQI for PM2.5 at the house in Welches, Oregon — a 24-hour-average quantity, taken as the highest 24-hour AQI value touching each calendar day, on the local monitor scale that a phone app displays (already bias-corrected from the raw model, and I applied no further correction of my own). The headline number is the single worst of the three trip days, Aug 28, 29, and 30 — not their average.”
Updated daily at 5am. A convenience, not an authority -
if officials issue an evacuation order, follow it.