Acute radiation effects

Effects that are caused by (usually short-term) exposure to radiation and that occur immediately after the exposure.

Source: GreenFacts

For example, one effect of intense radiation exposure is a rapid browning of the skin, known as a nuclear tan.

Source: 4engr.com Dictionary 

Acute radiation syndrome (ARS) - Radiation

GreenFacts Summary on the Chernobyl Nuclear Accident:

• 3.5 How did radiation affect plants and animals?

Chernobyl

Fukushima accident