Mt Hood · Aug 28-30 · -63 days out Updated Fri Oct 30, 5:00 AM · refreshes daily at 5am

Still on, but worth watching.

6 in 10chance the weekend is fine - clear or lightly hazy

Late August at Welches is usually clean Pacific air, and that is still the single most likely weekend you get: hazy sunsets, maybe a smell of smoke in the morning, and nothing that stops you hiking. The risk is not vague — a roughly 94,000-acre fire is burning 17 miles straight east at the same elevation line as the house, and the one weather pattern that would push its smoke down the Zigzag valley happens on about a third of days in this calendar window.

Our best guess for the worst single day is around the upper 80s on the AQI scale, which is breathable for healthy adults, but roughly a one-in-five chance that day lands above 150, where you cancel the hike and stay indoors.

Known now5 of 5 forecast sources already cover your dates

No horizonFire size and containment are observations, not forecasts — they can move this on any day

Decide byAug 23

What would change this

Evacuation zone at the housenone
US-26 open, Portland to Welchesopen
Air at Estacada28 · Clear
Nearest fire outside 10 miles17.4 mi · Grasshopper
Wind pushing smoke our wayno - ESE at 2 mph

So what are the odds?

If we ran this weekend 100 times, here is how they would split. Hover a row to pick it out of the dots.

2 in 1024%	Clear weekend AQI 0-50 Onshore marine flow all three days, Mt Hood sharp and visible from the Mt Hood Village meadow, cool mornings, no smoke smell, everything open.	nothing
4 in 1038%	Hazy but fine AQI 50-100 Milky white sky, orange sun at sunset, a faint campfire smell in the valley at dawn that burns off by late morning; the mountain looks washed out but visible.	Shift hard hikes to morning, keep the windows closed overnight, anyone asthmatic skips the long climb.
2 in 1022%	One smoky day AQI 100-150 One morning you wake up and can't see the ridgeline across the Salmon River; visible haze indoors, eyes sting on a walk, Hood invisible all day.	That day becomes an indoor day — no hiking, no outdoor cooking, run a purifier or the furnace fan with a MERV-13 filter, drive west to Sandy if someone needs out.
2 in 1017%	Real smoke episode AQI 150+ Brown-grey air with ash flecks on car hoods, sun a dull red disc at noon, smoke smell inside the house, headache and sore throat within an hour outdoors.	Cut the trip short or relocate toward the coast; anyone with asthma, a heart condition, or a young kid should not be there at all.

Clear AQI 0-50

You can see the mountain. Nobody notices anything.

Hazy AQI 50-100

Visible haze, ridgelines soften, faint campfire smell.

Smoky AQI 100-150

Distinctly smoky, orange sun, eyes sting a little.

Bad AQI over 150

Mountain invisible. You smell it indoors.

Where the fires are

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: High Lava (2,899 acres, 37.0 mi N).

An outline is only as current as the last mapping flight, which is not the same as when this page refreshed. Outlines flown — Grasshopper Sep 15 · Austin Sep 16. The oldest is Grasshopper, 45 days behind. Acreage and containment are refreshed far more often than the outlines are re-flown — those figures were last updated Sep 29, 4:26 PM, 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.

Day by day

Fri Aug 28

Hazy

likely 62 - could reach 145

19% chance of a smoky day

Sat Aug 29

Hazy

likely 62 - could reach 152

22% chance of a smoky day

Sun Aug 30

Hazy

likely 62 - could reach 150

21% chance of a smoky day

The specific odds

All three days clear22%

At least one smoky day (100+)40%

Two or more smoky days22%

At least one bad day (150+)18%

US-26 closed during the trip2%

Evacuation level at Welches6%

The one thing that would bring smoke here

Long-range wind signal unavailable this run.

When we'll actually know more

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.

Hover a dayto see the forecast we logged that morning and how much was known.

▲ Since 2026-08-10 the forecast has moved worse (+46 on the likely worst day) across 81 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
now	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
now	Air-quality / smoke model (CAMS) actual AQI at the house · reaches 6 days out

Why we think this

The controlling mechanism is transport direction, not fire size: Welches sits on the west slope and spends most late-August days under onshore Pacific flow, which is why 28 sampled days in this window produced nothing above 100 and a worst day of 91. But the terrain note in the evidence is wrong in an important way — I checked the perimeter coordinates, and Grasshopper's western lobe reaches about 121.60W at 45.31N, essentially due east of the house at the same latitude (bearing 94 degrees, 17.4 miles), while Mt Hood's summit is north of that line; the smoke path through the Government Camp/Barlow gap and down the Zigzag-Salmon River drainage is open, so the mountain shields nothing. That makes the climatological 31% offshore-day rate the real hinge, and with no ensemble available for the trip dates I cannot discount it — the measured local season anomaly of 1.0 is reassuring but it was computed over the last 30 days, which is late October, well after the fire season, so it says little about late August. Against that, a fire at this stage of its life produces far less flaming-front smoke than a running fire, west-slope valleys flush quickly once onshore flow returns, and nearly 2.34 million statewide acres are dominated by east-side fires that never reach this address. Weighing both directions, I land modestly above the 49-median climatology for the worst of three days, with most of the probability mass still in the hazy-but-breathable range and roughly a fifth of it in genuinely unhealthy air.

A normal late August here is Clear - median AQI 49 across the last 4 years. On these exact dates: 2025: 64 · 2024: 41 · 2023: 44 · 2022: 44.

We are forecasting a worst day of 88, 39 points above that base rate. That departure rests entirely on the reasoning above; judge it for yourself.

What the bad version needs:
A thermal ridge builds over the interior Northwest and surface pressure rises east of the Cascades, turning the flow offshore/easterly for 24-48 hours (happens on about 31% of days in this calendar window). → Grasshopper's western lobe — which reaches to roughly 121.60W at 45.31N, the same latitude as the house, not behind Mt Hood's summit — puts up smoke that is carried west through the Government Camp/Barlow gap and subsides down the Zigzag-Salmon River drainage. → Night and morning inversions pool that smoke in the valley floor where the house sits, so the 24-hour average stacks instead of mixing out; a second day of the same pattern pushes it past 150.
First visible signal: The phone weather app showing wind from the E or NE at Government Camp/Welches instead of from the W, plus hot, dry, dropping-humidity days — and the EPA Fire and Smoke Map turning orange on the east side of the crest the day before it reaches you. - about 2 days ahead

Key drivers, and what would change our minds

Fires within 60 miles

16.2 mi	Clear Lake Pile Rx-East SE	size not yet reported
16.5 mi	Timber Lake/Ripplebrook Admin Piles Rx - West SSW	size not yet reported
16.5 mi	Fawn Stew Piles Rx - West SSW	size not yet reported
17.2 mi	Podunk Admin Piles Rx - West SW	size not yet reported
17.4 mi	Grasshopper E	93,971 acres · 98% contained
18.3 mi	Austin S	12,888 acres · 98% contained
18.4 mi	Stone Ck/Clackamas Guard Station Rx Piles- West SSE	size not yet reported

The biggest hole in this forecast: 5 of the nearby fires (Clear Lake Pile Rx-East, Timber Lake/Ripplebrook Admin Piles Rx - West, Fawn Stew Piles Rx - West and 2 more) have no size reported yet. Whether those are 300-acre creepers or 20,000-acre runners is most of the answer.

Pack this regardless

Two or three HEPA air purifiers sized for the main living room and the bedrooms
N95 or KN95 respirators, a couple per person (surgical masks and bandanas do nothing for PM2.5)
Rescue inhalers and any heart or lung medication, carried rather than packed
A MERV-13 furnace filter that fits the house system, plus tape to seal a window AC
An indoor plan for one washed-out day: cards, a projector or streaming stick, groceries so nobody has to drive to Sandy
Full gas tank and a downloaded offline map, in case US-26 is slow or restricted

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.

Watch list, and getting there

Current and forecast PM2.5 at Welches/Government Camp - Any sensor in the Zigzag valley reading above 75 for more than six hours, or a smoke plume drawn over the crest toward US-26 (EPA AirNow Fire and Smoke Map (fire.airnow.gov))
Wind direction in the trip-window forecast - Wind from the E/NE on two or more consecutive trip days, or any Red Flag Warning for east winds in the Cascades (NWS Portland point forecast for Welches (forecast.weather.gov))
Grasshopper acreage and containment - Containment falling, or acreage growing more than ~5,000 acres in a day, or any growth reported west of the crest (InciWeb / Oregon Dept of Forestry fire dashboard)
Evacuation levels for Clackamas County east of Sandy - Any Level 1 (Be Ready) zone that includes Welches or Mt Hood Village (Clackamas County Sheriff / Genasys Protect map)
New starts within 30 miles - A new fire west of the crest in the Sandy, Salmon River, Bull Run, or Clackamas drainages at any size (Oregon ODF / Watch Duty app)

Sandy	16.9 mi
Brightwood	15.3 mi
Welches	17.3 mi

Distance from each point on the drive in to the nearest fire. TripCheck is the authority on closures.

If we wanted cleaner air, where would we go?

Ranked by how bad these dates have historically been at each place. The coast is not just cleaner today — it sits upwind of everything burning, so it only smokes during an east-wind reversal, which is the same event that would smoke out the house.

“Bad day / typical” is what the air actually did on Aug 26 – Sep 1 in 2022, 2023, 2024 and 2025 — 28 days per place. The first number is the bad day: one day in ten was worse than this. The second is the typical day, the middle of the range. We rank on the bad day rather than the typical one, because the bad day is what would spoil a weekend.

Both are converted onto the same scale as the “now” column, so every AQI figure in this table is comparable. That conversion matters more than it sounds: the model these come from runs about 2.5× high on the coast but close to true inland, so before correcting it the coast looked far worse than it is.

Place	Bad day / typical	Now	Official forecast	Next 5 days	Nearest fire
Astoria coast	19 / 16	14 Clear	Good	▲ worsening	84 mi · High Lava
Long Beach, WA coast	19 / 17	14 Clear	—	▲ worsening	97 mi · High Lava
Newport coast	25 / 21	37 Clear	Good	▲ worsening	101 mi · Austin
Welches / Mt Hood booked	30 / 22	34 Clear	Good	▲ worsening	17 mi · Grasshopper
Manzanita coast	30 / 28	54 Hazy	—	▲ worsening	87 mi · High Lava
Cannon Beach coast	31 / 27	54 Hazy	—	▲ worsening	88 mi · High Lava
Pacific City coast	32 / 29	54 Hazy	—	▲ worsening	93 mi · Austin
Hood River east of crest	46 / 30	29 Clear	Good	▲ worsening	21 mi · Grasshopper
Silver Falls valley	50 / 37	49 Clear	—	▲ worsening	31 mi · Austin
Portland valley	67 / 54	61 Hazy	Good	▲ worsening	36 mi · High Lava
McMinnville valley	76 / 53	59 Hazy	Good	▲ worsening	57 mi · Austin
Bend east of crest	78 / 45	87 Hazy	—	▲ worsening	60 mi · Deep Canyon

What each column covers, and where it comes from

Field	Period it covers	What it is
Air right now	10/30/26 4:00 PDT	Nearest EPA/AirNow ground monitor to each place, within 45 miles airnow.gov
Official forecast	issued 10/30/26 by Washington Department of Ecology	Next published outlook for that reporting area — a human forecaster's call Oregon DEQ via AirNow
Next 5 days	today's model run, covering 2026-11-03	Direction only. Copernicus CAMS global air-quality model open-meteo.com
Bad day / typical	Aug 26 – Sep 1 in 2022, 2023, 2024, 2025 (28 days each)	CAMS reanalysis for those exact dates, then converted to the monitor scale open-meteo.com
Scale conversion	median of 14 daily model-vs-monitor pairs, 2026-10-09 to 2026-10-22	Median of daily model-vs-monitor ratios — the bias differs by place, from 0.351 on the coast to 1.066 inland AirNow daily archive
Nearest fire	queried Oct 30 5:00 AM	Perimeter polygons of fires over 100 acres, distance to the burned edge NIFC WFIGS

Every AQI figure above is on the ground-monitor scale — the same thing your phone shows. n/a means the model and the monitors disagree so sharply at that spot that we cannot honestly place it on that scale (steep terrain inside a coarse model grid cell — the Gorge is the usual culprit); those rows are sorted by today’s reading instead.

How this is made, and what it cannot do

Fire perimeters from NIFC, evacuation zones from Oregon OEM, weather and alerts from NWS, air quality from AirNow (Estacada, 18.3 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 91, 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? Across 380 scored forecast-days, the air-quality model beat both simple baselines at 1 of 5 lead times. Where it does not, this page should not be trusted to out-guess them either.

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.

Updated daily at 5am. A convenience, not an authority -
if officials issue an evacuation order, follow it.