Live on the globe now: 34 tracked
This layer plots active severe-weather alerts issued by the US National Weather Service. Each marker is one currently in-effect alert that carries a map polygon - tornado warnings, severe thunderstorm warnings, flash flood and flood warnings, winter storm warnings, red flag (fire weather) warnings, special weather statements and similar products. Alerts are colored and sized by the NWS severity field (Extreme, Severe, Moderate, Minor), so the most dangerous events stand out at a glance. The data comes straight from the NWS public API at api.weather.gov, using the active-alerts feed (actual, alert-type messages). Coverage is the United States and its territories, since that is what NWS issues. This page polls the feed about every two minutes, so warnings appear and clear close to when forecasters issue or cancel them. Click any alert to inspect its event type, severity, urgency and certainty, the issuing office, the affected area description, effective and expiry times, and the headline and instruction text. Note that NWS alerts referencing only zone codes without a polygon are not mapped here; this view shows polygon-based alerts placed at the polygon centroid. It is one of around 29 live layers on the overwatch.earth globe.
Data source: US NWS
Directly from the US National Weather Service public API at api.weather.gov, specifically the active-alerts feed filtered to actual, alert-type messages. NWS is the official US government source for severe-weather warnings.
The feed is polled roughly every two minutes, so new warnings appear and expired or cancelled ones drop off within a couple of minutes of NWS updating them.
Markers are styled by the NWS severity field - Extreme, Severe, Moderate or Minor - so higher-severity alerts like tornado warnings stand out against advisory-level products.
No. The National Weather Service issues alerts for the United States and its territories, so this layer is US coverage only. Other overwatch.earth layers handle global hazards.