PM2.5 vs Ozone: How the Two Main AQI Pollutants Differ
Nov 9, 2026
Fine particles and ground-level ozone both drive the Air Quality Index, but they form differently, peak at different times and come with different EPA health messages.
Guides
Plain-English explainers: what magnitude, alerts, AQI, hurricane categories and volcano alert levels mean, and where the official information comes from.
Hurricane Categories Explained: The Saffir-Simpson Wind Scale
Nov 9, 2026
The National Hurricane Center rates hurricanes by one number: peak sustained wind. Here is the official table in mph, knots and km/h, and what a category cannot tell you about surge and rain.
Heat Alerts Explained: Extreme Heat Warning, Watch and Advisory
Nov 9, 2026
The National Weather Service renamed its Excessive Heat alerts in March 2025, and each local office sets its own heat thresholds. Here is what the current heat alerts mean and how the HeatRisk scale fits in.
Induced Earthquakes in Oklahoma, Texas and Kansas Explained
Nov 9, 2026
Oklahoma went from about 1.5 magnitude 3 earthquakes a year to about 2.5 a day. Here is what the USGS and state geological surveys say caused it and how the numbers have changed.
How to Get Emergency Alerts: Phone, Weather Radio and Local
Nov 9, 2026
Official alerts reach you through several channels, and no single one carries everything. Here is what each channel sends, how to check your phone settings and how to find your local alert system.
Magnitude vs Intensity: Why One Quake Feels Different in Each Town
Nov 9, 2026
One earthquake gets one magnitude but many intensity values. Here is how USGS rates shaking town by town, and why a nearby moderate quake can feel stronger than a distant big one.
Air Quality Index (AQI) Explained: Categories, Colors and Ranges
Nov 9, 2026
What each AQI number and color means, which pollutants it covers, why the current reading on AirNow is a NowCast, and the health messages EPA attaches to each category.
When Is Hurricane Season? Official Dates and Peaks by Basin
Nov 9, 2026
Official season dates from the National Hurricane Center for the Atlantic, eastern Pacific and central Pacific, with peak periods, average first-storm dates and how NOAA builds its seasonal outlooks.
How Yellowstone Is Monitored: Earthquakes, Ground Motion, Alerts
Nov 9, 2026
The Yellowstone Volcano Observatory reports earthquakes, ground motion and hydrothermal activity every month. Here is what those numbers mean and what USGS says about the chance of an eruption.
Flash Flood Warning vs Flood Warning: What Each Alert Means
Nov 9, 2026
The National Weather Service separates sudden flash floods from slower river flooding, and only some flash flood warnings reach your phone. Here is how the flood alerts differ and what the NWS advises.