The 'DANA' weather system behind Spain's extreme rainfall

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The extreme conditions in eastern Spain which saw Valencia get a year’s worth of rain in just eight hours can be blamed on an event locally known as Depresion Aislada en Niveles Altos (DANA).

This weather situation occurs when the jet stream high up in the atmosphere meanders like a river and creates a cut off area of low pressure.

That can become slow moving or almost stationary, with surrounding high pressure blocking it and allowing heavy rain to fall in the same region.

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Cool air from the north is drawn across the warmer Mediterranean waters, a situation known to bring severe weather to the area in late summer and autumn when the sea surface temperature is high.

That temperature difference can then enhance storm development and rainfall totals.

But rainfall amounts on Tuesday were extreme, with AEMET, Spain’s meteorological department, reporting 491mm in just eight hours at Chiva, near Valencia.

That’s a staggering amount of rain and more than a year’s worth.