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 San Antonio, Texas?

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

San Antonio 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 4 other listed targets in range of San Antonio. The nearest is Austin, about 74 miles to the northeast.

Winds high above the continental United States blow from the west more often than not, and none of the listed targets in range lies to the west of San Antonio. On a typical day that works in the city's favor, but the pattern can be quite different on any given day, which is what the map below shows.

Listed targets in range of San Antonio (illustrative, not a prediction)
Potential targetTypeFrom San Antonio
San Antonio, TXMetro areaHere
Austin, TXMetro area74 mi northeast
Houston, TXMetro area189 mi east
Dyess AFB, TXMilitary site222 mi north-northwest
Dallas, TXMetro area252 mi north-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.