Tornado Alley (PROG)

[fuagf]

Fair point. I'd say they just assumed anyone interested would know what bleaching there meant.

Umm, it's not explained exactly in the Guardian link below either.

Super El Nino Likely as Huge Warm Water Wave Hits West Coast, Extreme Marine Die Off Developing
[...]
The warming that last year's huge Kelvin wave brought started a global coral bleaching event .. http://www.theguardian.com/environment/2015/feb/19/worlds-coral-reefs-face-major-bleaching-event-this-year-us-agency-warns .. is likely to get much worse after this year's huge wave of warm water spreads up and down the coasts of north and south America.
https://investorshub.advfn.com/boards/read_msg.aspx?message_id=113296034

Here we go - What is coral bleaching?

When corals are stressed by changes in conditions such as temperature, light, or nutrients, they expel the symbiotic algae living in their tissues, causing them to turn completely white.



Can coral survive a bleaching event? If the stress-caused bleaching is not severe, coral have been known to recover. If the algae loss is prolonged and the stress continues, coral eventually dies. Download this infographic: In English | In Spanish

Warmer water temperatures can result in coral bleaching. When water is too warm, corals will expel the algae (zooxanthellae) living in their tissues causing the coral to turn completely white. This is called coral bleaching. When a coral bleaches, it is not dead. Corals can survive a bleaching event, but they are under more stress and are subject to mortality.

In 2005, the U.S. lost half of its coral reefs in the Caribbean in one year due to a massive bleaching event. The warm waters centered around the northern Antilles near the Virgin Islands and Puerto Rico expanded southward. Comparison of satellite data from the previous 20 years confirmed that thermal stress from the 2005 event was greater than the previous 20 years combined.

Not all bleaching events are due to warm water.

In January 2010, cold water temperatures in the Florida Keys caused a coral bleaching event that resulted in some coral death. Water temperatures dropped 12.06 degrees Fahrenheit lower than the typical temperatures observed at this time of year. Researchers will evaluate if this cold-stress event will make corals more susceptible to disease in the same way that warmer waters impact corals.
https://oceanservice.noaa.gov/facts/coral_bleach.html