Live from the National Weather Service
Fire weather today
Checked every time you open this page. Most days it's quiet. On the days it isn't — wind event, single-digit humidity, red flag flying — this is the first thing we look at in the morning, and it should be yours too.
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Pushes the fire, carries embers a mile ahead, and turns a spot fire into a front. The single biggest driver of bad days.
Below about 15%, fine fuels shed their moisture in hours. Single digits is when things get genuinely scary.
By late summer, LA's hillside grass is basically standing kindling. Fuel moisture decides whether a spark catches at all.
From the account
Latest posts
Reports go out on X the moment we have them — this is the recent feed.
Interactive
The spread lab
This is the fun part. Tap the terrain to drop a spark, drag the compass to set the wind, and watch the fire stretch into a burning ellipse — head out front, flanks on the sides, heel crawling behind. Then crank the wind to 35 and see why nobody sleeps during a Santa Ana event.
Light greens are grass — it burns fast and dies out fast. Dark patches are heavy brush that burns hotter and longer. Grey is bare rock, and the shading shows the hills: watch fire sprint up a slope and stall coming down the far side. Above about 16 mph the fire starts throwing embers ahead of itself and lighting spot fires downwind — the thing that makes real wind-driven fires nearly impossible to stop.
Fire literacy
Learn the language
The questions people ask us most, answered straight.
What does "40% contained" actually mean?
Containment is how much of the fire's edge has a control line around it — not how much of the fire is out. A fire can be 90% contained and still burning intensely inside the lines. Watch the acreage growth alongside containment to read how a fight is really going.
Why are Santa Ana winds such a big deal?
They're hot, dry winds that pour from the high desert toward the coast, usually in fall. They crash the humidity, pre-dry every fuel on the hillside, and push fire downslope toward neighborhoods — the reverse of normal fire behavior, and the setup behind most of LA's worst fires.
What's a red flag warning?
The National Weather Service's signal that conditions could make any new start spread dangerously fast: strong wind, low humidity, dry fuels. It's about the weather, not an actual fire. On red flag days, one spark from a chain dragging on a freeway can become a major incident in an hour.
Evacuation warning vs. evacuation order
A warning means get ready: pack, load the car, plan two routes out. An order means leave now. Wind-driven fires can outrun traffic — the people who wait to see the flames are the ones who end up driving through them.
Why does fire run uphill?
Flames lean into the slope, preheating the fuel above them, so the fire climbs far faster than it descends — roughly doubling its spread rate on steep ground. It's why canyon communities get so little warning, and you can watch it happen in the lab above.
Where do your reports come from?
Public sources anyone can verify: CAL FIRE incident pages, ALERTCalifornia camera networks, National Weather Service products, and agency radio traffic. When a number is an estimate, we say so. If we get something wrong, we correct it in a follow-up post, visibly.
Reference
Glossary
Tap a term.
The account
About PyroCast
PyroCast started with a simple frustration: when there's a smoke column over the ridge, finding out what it actually is takes way too long. Scanner apps, camera feeds, agency pages — we live in all of them so you can just check one place.
We cover Los Angeles and Ventura counties: new starts, acreage, containment, fire weather, and plain-language explanations of what it all means for the people who live here.
Behind the account is a years-long obsession with fire behavior and building fire simulations. The spread lab on this page is a small taste of it — the same logic we use when we look at a new start and try to call which way it'll run.
Where the data comes from
- CAL FIRE incident pages and public feeds
- National Weather Service alerts and forecasts
- ALERTCalifornia camera network
- Agency radio traffic for early reports, always labeled as unconfirmed