Right now the air at the house is clean, and the pattern keeping it clean — cool ocean air pushing inland every morning, with fog in the valley — is the normal late-August setup for the west side of Mt Hood. The big fire seventeen miles east will still be burning on your dates, so the entire question is wind direction, and the most likely outcome is a worst day somewhere in the teens to thirties, which is ordinary summer air.
There is roughly a one-in-six chance an east wind pulls that fire's smoke down the Zigzag valley for a day or two and makes one day genuinely unpleasant — worth packing for, not worth cancelling over.
If we ran this weekend 100 times, here is how they would split. Hover a row to pick it out of the dots.
| 6 in 1057% | Clear weekend AQI 0-50 Morning fog burning off to blue sky; maybe a milky band low on the eastern horizon near the mountain, but the air smells like fir, not campfire, and nobody comments on it. | nothing |
| 3 in 1025% | Hazy but fine AQI 50-100 Flat white sky, the ridgelines across the valley look washed out, a faint smoke smell at breakfast that fades by afternoon. Healthy people are fine; one or two people with asthma notice it. | Do the hike in the morning before the valley heats up; keep windows shut overnight and run a filter in whichever room the sensitive folks sleep in. |
| 1 in 1011% | One smoky day AQI 100-150 The sun is an orange disc you can look at, you can taste the smoke, the far side of the valley disappears. Ash flecks possible on car hoods. One day of this, then it clears or drops back to haze. | Cancel outdoor plans for that day, keep everyone inside with the box-fan filter running, N95s for anyone who goes out, and consider a day trip west toward Portland or the coast where the air is usually clean. |
| 1 in 107% | Real smoke episode AQI 150+ Visibility under a mile, headlights on at midday, indoor air noticeably smoky even with windows shut, everyone's eyes and throat hurt. Persists two to three days rather than one. | Leave, or never come. If you're already there, drive west on US-26 — you're usually out of it by Sandy or Gresham. Anyone with asthma, heart disease, a pregnancy, or a small child should not stay. |
Fires near the house, drawn at their real shape from the federal perimeter data, over USGS terrain. Dashed rings are distance from the house; the shaded wedge is the only direction an east wind could carry smoke here from. Point at a fire for its details.
Solid dots are fires too small to draw at this scale but whose size is known. A dashed circle would mean a fire that has been located but has no published perimeter - size unknown, not small.
Beyond this frame, and too far to threaten the house but close enough to add regional haze: Bench (67,071 acres, 45.5 mi SSE), Ten Mile (4,834 acres, 56.7 mi SE), Beachcomb (2,346 acres, 49.5 mi SSE), High Lava (1,211 acres, 38.9 mi NNW).
An outline is only as current as the last mapping flight, which is not the same as when this page refreshed. Outlines flown — Grasshopper Aug 11 · Austin Aug 10 · Mitchell Aug 9 · The Narrows Aug 8. The oldest is The Narrows, 5 days behind. Acreage and containment are refreshed far more often than the outlines are re-flown — those figures were last updated Aug 13, 11:54 AM, so a fire may already be larger than the shape drawn for it.
Terrain: USGS 3DEP (public domain). Roads and water: © OpenStreetMap contributors (ODbL). Fire perimeters: NIFC.
Want to check it yourself, or see the rest of the state? The Oregonian's wildfire tracker is live and updates every 15 minutes.
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 better (-11 on the likely worst day) across 4 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 |
| now | 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 dominant fact is that a large, poorly contained fire (Grasshopper, 85k acres at 20%) sits 17 miles east and will still be producing smoke on Aug 28-30 — fires that size in a record-drought Oregon year routinely burn into late September, and the first season-ending west-slope rain is climatologically mid-September at the earliest. Despite that, the monitor 8.7 miles away reads 13 right now, which tells you the transport, not the fuel, is the binding constraint: the summer marine pattern vents the Sandy valley westward and pushes fire smoke away from the house, and that pattern held all week with fog and light NW winds. The failure mode is an offshore pressure gradient — and I want to be explicit that Mt Hood does NOT protect you from it, because east wind channels down through the Cascade gaps into the Zigzag/Sandy corridor and Welches sits at the outlet, which is exactly why the 2020 and 2017 west-side events hit valleys like this one so hard. Two fires are on the house's own side of the crest with no terrain in between — Austin at 19 miles S (1,430 acres, 0% contained) and Regan Hill at 18 miles W, whose size the pack doesn't report — and the westerly one is upwind in the ordinary onshore flow, which is part of why I'm fattening the 50-100 band above what pure climatology would give.
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 31, 19 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 | 2 acres |
| 17.4 mi | Grasshopper E | 85,114 acres · 20% contained |
| 17.8 mi | Regan Hill W | size not yet reported |
| 19.4 mi | Austin S | 1,430 acres · 0% contained |
| 20.4 mi | Austin Non-Stat S | size not yet reported |
| 27.1 mi | Gorton Creek NNE | size not yet reported |
The biggest hole in this forecast: 3 of the nearby fires (Regan Hill, Austin Non-Stat, Gorton 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.
How thin the history is. The air-quality record for this spot begins in 2022, so "normal" here is built from just 4 years (2022, 2023, 2024, 2025). In those 28 sampled days the worst single day was AQI 22, and none reached 100.
That record has never seen a bad Oregon smoke year — not 2020, when Portland sat above AQI 500 for days, nor 2017, 2018 or 2021. So the base rate below is drawn entirely from calm years, and the upper end of our range is an estimate rather than something history has shown us. It is the main reason not to read the good news too confidently.
Are these forecasts any good? Accuracy checking started Aug 13. 0 forecast-days scored so far — far too few to claim anything. This is the only part of the page that can ever be proved wrong.
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 EPA AQI for PM2.5 computed as a 24-hour average concentration — the single highest such 24-hour value touching any of Aug 28, 29, or 30 at the Welches house, reported on the local monitor scale that a phone app like AirNow would display, not the raw model scale. 'Worst day of trip' is the maximum of those three daily values, not their average, and I have applied no bias correction of my own on top of the calibration already in the evidence.”
Updated daily at 5am. A convenience, not an authority -
if officials issue an evacuation order, follow it.