Dissemination and its gaps

A warning that nobody receives is a file on a server. This lesson follows the product out of the office and finds the places it stops.

The chain out of the office

NWWS

NOAA Weather Wire Service. The bulk feed of text products, which is what media, vendors and downstream systems consume.

GOES / EMWIN

The Emergency Managers Weather Information Network, broadcast down from the GOES satellites. The same warning text, arriving from orbit to anything with a receiver and a view of the sky, which is the point: it needs no internet connection and no phone network.

NWR / SAME

NOAA Weather Radio, with Specific Area Message Encoding so a receiver can stay silent for events outside its area.

EAS

Emergency Alert System. The broadcast interrupt on radio and television.

WEA via IPAWS

Wireless Emergency Alerts, routed through FEMA's IPAWS. This is the one that reaches a phone with no app installed and no subscription.

Media and apps

Broadcasters and third-party services, this one included, that consume the feed and present it. Fast, ubiquitous, and not the official channel.

What actually sets off a phone

Not everything, and the list is shorter than most people assume. The National Weather Service has sent WEA since June 2012, and it sends it only for warnings that need somebody to act in the next few minutes.

Two things are worth reading out of that table. The first is that the test is imminence, not danger. Blizzard and ice storm warnings came off the list in 2013 because they are issued well ahead of the weather, not because a blizzard is survivable. A snow squall warning, issued while it is happening, is on the list for exactly that reason.

The second is that the damage-threat tag from Lesson 5 is what opens the gate for the two warnings you will meet most often. A severe thunderstorm warning reaches phones only at the destructive tier, and since 2019 a flash flood warning reaches them only at considerable or catastrophic. The tag is not decoration. It decides who finds out.

Weather arrives as one of the four kinds of WEA: national alerts, imminent threat, AMBER alerts and public safety messages. All of the above are imminent threat alerts, and a carrier is permitted to let a subscriber switch that whole category off. Only national alerts cannot be blocked.

Those answer most of the complaints you will hear in the field. A neighbor who says the alert never came through usually received exactly what the system is designed to send. The expectation was wrong, not the delivery.

The gap between receiving and acting

The Joplin Service Assessment documented a durable finding: people who receive a warning frequently do not act on it immediately. They look for confirmation first, from a second channel, a neighbor, a window, the sky. The warning starts a decision rather than ending one.

Where WxAlerts sits

Downstream, and unofficial. This service redistributes NWS products and adds its own detection data on top. It is not a government source and not a replacement for one. If this site and NOAA Weather Radio disagree, the radio wins. How the feed reaches us and what we do to it is documented in [how alerts work](/docs/how-it-works/alerts/).

Check yourself

Your neighbor got no alert on their phone for a severe thunderstorm warning that covered their house, and they have never touched their alert settings. Why?

1. Severe thunderstorm warnings do not trigger WEA unless they carry the destructive damage threat tag
2. Their phone was outside the warning polygon
3. WEA only operates at night
4. The warning had not been relayed to NWWS yet

Sources

1. weather.gov WEA and NOAA Weather Radio pages
2. NWS EMWIN program documentation
3. FEMA IPAWS documentation
4. FCC consumer guide, Wireless Emergency Alerts
5. Wikipedia, Wireless Emergency Alerts, for the per-product eligibility summary
6. NWS Joplin Service Assessment (2011)