Fallout Weather Upper-air winds, read for fallout

Educational tool. Not an emergency alert system or official guidance. In an emergency, follow instructions from authorities.

Where would today's winds carry fallout near Phoenix, Arizona?

The map below estimates where today's forecast upper-air winds would carry fallout from each potential target near Phoenix, and whether any of it could reach the city.

Phoenix is itself on this site's list of potential targets. Close to an explosion, blast and heat are the main dangers, and fallout would begin within minutes whatever the wind.

There are 3 other listed targets in range of Phoenix. The nearest is Nellis AFB / Las Vegas, about 255 miles to the northwest.

Winds high above the continental United States blow from the west more often than not, so targets to the west of Phoenix are upwind most often: San Diego. On any given day the pattern can be quite different, which is what the map below shows.

Listed targets in range of Phoenix (illustrative, not a prediction)
Potential targetTypeFrom Phoenix
Phoenix, AZMetro areaHere
Nellis AFB / Las Vegas, NVMilitary site255 mi northwest
San Diego, CAMetro area299 mi west
Kirtland AFB / Albuquerque, NMMilitary site334 mi east-northeast

Many factors affect where fallout travels and how dangerous it is. This educational tool takes only three into account: the forecast winds from the ground up to the top of the mushroom cloud, an assumed weapon size, and an assumed burst type (on the ground or in the air). The target list is illustrative, not a prediction. How to read the map.

Official preparedness guidance

This is a summary of public guidance from Ready.gov and the CDC. It does not come from this map, and the map should not be used to make emergency decisions.

  1. Get inside. Official guidance is to get into the nearest solid building, as deep and central as possible: a basement, or the middle of a large building.
  2. Stay inside. Official guidance is to stay sheltered for at least 24 hours unless authorities say otherwise, because fallout radiation is strongest in the first hours and decays quickly.
  3. Stay tuned. Follow official instructions, for example by battery-powered or hand-crank radio.

Read the sources: Ready.gov: Radiation Emergencies and CDC: Radiation Emergencies. Our fuller summary lists each source.