Cold drop

A cold drop^[a] is a term used in Spain and France that has commonly come to refer to any high impact rainfall event occurring in the autumn along the Spanish Mediterranean coast or across France.^[1] In Europe, cold drops belong to the characteristics of the Mediterranean climate.^[2][3]

A stationary cold low, in which a cold drop is found.

The Spanish-language name of gota fría was directly adapted from the term Kaltlufttropfen introduced by German meteorologists, and became very popular in 1980s Spain as a blanket term to refer to any high-impact rainfall event.^[4]

In the Spanish Levante, these events are typically caused by the interaction of upper-level low pressure systems strangled and ultimately detached from the zonal (eastward) circulation displaying stationary or retrograde (westward) circulation with humid warmer air masses that form over an overheated Mediterranean Sea in the Autumn. The Spanish equivalent of cut-off low is DANA (Depresión Aislada en Niveles Altos).^[4] Such recurring synoptic configurations are not necessarily associated to cold drop events.^[b]

Occurrence

See also: List of cold drop events

Spain

If a sudden cut off in the jet stream takes place (particularly on the Atlantic Ocean), a pocket of cold air detaches from the main jet stream, moving southward over the Pyrenees into the warm air over Spain, causing its most dramatic effects in the southeast of Spain, particularly along the Spanish Mediterranean coast, especially in the Valencian Community. The torrential rain caused by a cold drop can result in devastation caused by torrents and flash floods.

This phenomenon is associated with extremely violent downpours and storms, but not always accompanied by significant rainfall. For this, high atmospheric instability in the lower air layers needs to combine with a significant amount of moisture.^[6]

Disasters

The great Valencia flood on 14 October 1957 was the result of a three-day-long cold drop and caused the deaths of at least 81 people.

The Vallès floods on 25 September 1962 in the province of Barcelona were caused by a cold drop (gota fría),^[7] producing heavy rain, overflowing the Llobregat and Besòs rivers. The official death toll was 617.

On the night of 29-30 October 2024, a DANA event caused considerable loss of life and extensive damage, especially in the Valencian Community^[8] and the provinces of Albacete,^[9] Almería,^[10][11] and Málaga.^[12]

Other areas

Cut-off lows are apparent near the Sierra Nevada de Santa Marta in the Colombian Caribbean, with peaks surpassing 5 km in altitude in close proximity to a warm sea. They can also occur elsewhere in the southern hemisphere, such as in South Africa, Namibia, South America and southern Australia. In the northern hemisphere, besides Southern Europe and France, they can occur in China and Siberia, North Pacific, Northeastern United States and the northeast Atlantic.

See also

• Cold-core low
• Cold pool
• Polar vortex

Notes

1. Basque: tanta hotz; Catalan: gota freda; French: goutte froide; Galician and Spanish: gota fría
2. In the Summer, a stationary DANA located off the Western coast of the Iberia Peninsula may favor torrid temperatures as it induces south-north meridional flows (to its East).^[5]