Wildfire Exposure and Smoke

Every lookup shows two separate things about fire. They answer different questions, so they are kept apart.

	Question it answers	Where it appears
Wildfire exposure	How exposed is this location to wildfire, compared with the rest of Colorado?	Safety & risk
Burns and smoke	Is anything burning within reach right now, and is its smoke likely to get here?	Environment, next to air quality

A home in central Denver can have very low wildfire exposure and still sit under smoke for days. That is why they are not one number.

Wildfire exposure

This is our own rating, on a five-step scale: Very low, Low, Moderate, High, Very high. It is built from two official sources, and the facts behind it are shown next to it.

What goes into it

1. The land around the address. The USDA Forest Service publishes a wildfire hazard map of the whole country. We read it at the address and at twelve points around it, out to about half a mile, and compare the result with the rest of Colorado. You will see a line such as "Land within ½ mile ranks above 92% of Colorado for wildfire hazard."

   We look at the surroundings rather than the single spot under the house, because a house is "built-up land" on that map even when forest starts at the back fence.

2. Fires that have happened nearby. From the national interagency record of wildfire perimeters, we list wildfires that came within 10 miles, the closest one, and the largest.

How the level is set

• The starting level comes from the ranking: the top 5% of Colorado is Very high, the next 10% High, and so on down.
• If a wildfire of 100 acres or more came within 5 miles in the last 20 years, the level is raised one step, and the result names the fire.
• If less than a quarter of the land within half a mile can burn (a built-up neighbourhood with one park or vacant lot), the level is lowered one step, and the result says so.
• If nothing within half a mile can burn, the level is Very low.

What it is not

It is not a prediction that a property will or will not burn, and it is not an insurance rating. It does not know about a home's roof, vents, defensible space or the road out. Use it to compare locations and to decide what to ask next — your insurer, the local fire district and the Colorado State Forest Service can speak to a specific property.

Burns and smoke

This part is live. It is checked again on every lookup and is never taken from a saved report.

• Prescribed burns and wildfires within 75 miles. Each is listed with its distance and direction from the address, its size when known, and when it started. Smoke from a prescribed burn routinely travels this far and can linger for days, so the search is deliberately wide.
• Wind. Using the wind forecast for the address, we work out for how many of the next 48 hours the wind would carry smoke from each burn toward you. A burn 40 miles upwind matters; one 40 miles downwind mostly does not.
• Smoke overhead. NOAA analysts map smoke plumes from satellite imagery and grade them Light, Medium or Heavy. If one covers the address, the result says so — whatever is producing it.

The particle reading on the same card (PM2.5) is what the air near the ground actually measures. Smoke overhead does not always reach the ground, and ground-level smoke can come from a source too small to appear on a satellite image, so read the two together.

Limits you should know about

• Burns come from the interagency incident system that federal, state, county and local agencies report into. Not every burn is reported there. A small local burn announced only on a fire district's social media page may be missing or appear late. "No reported burns" means none were reported, not that none exist.
• Prescribed-burn entries older than two weeks are treated as finished and left out.
• Wind is a forecast. Terrain, inversions and overnight drainage winds move smoke in ways a single wind direction does not capture — mountain valleys in particular.
• If a source cannot be reached, its line is left out rather than shown as clear.

Sources

• Wildfire hazard: USDA Forest Service, Wildfire Risk to Communities (Wildfire Hazard Potential)
• Fire history and current incidents: National Interagency Fire Center
• Smoke plumes: NOAA Hazard Mapping System
• Wind forecast: Open-Meteo