Satellite Fire Detections Explained: What NASA FIRMS Hotspots Mean
Nov 9, 2026
What a satellite fire detection shows, which satellites supply NASA FIRMS as of November 2026, how fast the data arrives, and why a hotspot is not proof of a wildfire.
Guides
Plain-English explainers: what magnitude, alerts, AQI, hurricane categories and volcano alert levels mean, and where the official information comes from.
Wildfire Containment Explained: Percent Contained and Acres Burned
Nov 9, 2026
What “40% contained” really means, why acreage changes, how fires get their names, where official updates come from and how evacuation terms differ by state.
California Earthquake Faults: San Andreas, Hayward and San Jacinto
Nov 9, 2026
California has hundreds of active faults, but a few carry most of the attention. Here is what the USGS and the California Geological Survey say about them, with the official 30-year odds by region.
Winter Weather Alerts Explained: Storm, Blizzard, Ice and Cold
Nov 9, 2026
Winter storm, blizzard, ice storm, snow squall and the cold alerts the National Weather Service renamed in 2024: what each one means, with real criteria from local NWS offices.
What Causes a Tsunami, and Why Most Big Earthquakes Don’t
Nov 9, 2026
A tsunami starts when a large volume of ocean water is suddenly pushed out of place. Earthquakes do that most often, but only certain kinds, and landslides and volcanoes can too.
Watch vs Warning vs Advisory: What Each NWS Alert Means
Nov 9, 2026
The National Weather Service uses the same three words for tornadoes, floods, snow, heat and cold. Here is what each level means, who issues it and where to see the alerts in effect for your area.
Tropical Depression vs Tropical Storm vs Hurricane: Wind Thresholds
Nov 9, 2026
Depression, storm and hurricane are stages of one kind of system, separated by NHC wind thresholds. The name changes again in the western Pacific and Indian oceans.
Hurricane Watch vs Warning: What Each Alert Means and When It Comes
Nov 9, 2026
NHC times every tropical watch and warning to the first tropical-storm-force winds. Here are the official definitions for hurricane, tropical storm, storm surge and extreme wind alerts.
Volcano Alert Levels Explained: Normal, Advisory, Watch, Warning
Nov 9, 2026
Every USGS volcano update starts with two labels. One is written for people on the ground, the other for pilots, and they usually change together.
Earthquake Depth Explained: Shallow, Intermediate and Deep Quakes
Nov 9, 2026
Depth tells you how far below the surface an earthquake started. Here is how USGS classifies it, how it is measured and why early reports often show exactly 10 km.