Field Notes
Wildfire Basics
How to read wildfire smoke maps, understand the air-quality index, and know when the smoke near you will clear.
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Red Flag Warning: What It Means and What It Does Not
A Red Flag Warning is a National Weather Service product about weather, not about fire. It does not mean a fire is burning. It means that if one starts, conditions favor it spreading fast, and it usually arrives alongside a set of restrictions and, increasingly, a power shutoff.
N95s and Wildfire Smoke: The Fit Matters More Than the Filter
A properly fitted N95 filters the fine particles in wildfire smoke very effectively. A cloth mask does essentially nothing, a surgical mask does very little, and an N95 worn loosely does considerably less than the label suggests. Here is what works, what does not, and why.
Exercising in Wildfire Smoke: The Number That Should Change Your Plan
Exercise multiplies how much air you move through your lungs, sends it deeper, and bypasses the filtering your nose would otherwise do. That turns a moderate smoke day into a meaningful exposure. Here is how to read the AQI for activity, and where the real thresholds sit.
Level 1, Level 2, Level 3: What Wildfire Evacuation Notices Actually Mean
Two different evacuation systems are in use across the western United States, they use different words for the same thing, and in an emergency people frequently do not know which one their county uses. Here is what each level means and what you should already have done by the time you hear it.
Building a Clean Air Room: The Cheapest Thing That Actually Works
When smoke settles over a region for a week, the most protective thing available to most people is one room in the house with genuinely clean air. It costs less than a hundred dollars to build, it works, and almost nobody does it before they need it.
When Will the Smoke Clear? How Smoke Forecasts Work
The honest answer is "it depends on the wind" — but you can see it coming. Here's how.
AQI Explained: What the Air-Quality Numbers Mean
0 to 500, six colors, one question: is it safe to be outside? Here's how to read the AQI.
How to Read a Wildfire Smoke Map
Those gray blobs over your town aren't random. Here's how to read them — and where they'll drift.