Meteorological concepts III: The cold drop

Have you heard of the COLD DROP?

The COLD DROPThe extreme weather phenomenon, an extreme weather event, is particularly relevant for those working in agriculture and lawn care. This article provides a comprehensive overview of how it affects these sectors and what measures can be taken to mitigate its effects. In this article, we will look at what is cold drop?what are their causes and repercussionsand how we can protect ourselves from its effects.

What is Cold Drop?

The Cold Dropknown in meteorology as DANA (Isolated High-Level Atmospheric Depression) occurs when a cold air mass (at a certain altitude) is abruptly surrounded by warm air. The cold, dense air descends towards the earth's surface and forces the warm, humid air to rise, rapidly forming a cloud that causes heavy rainfall that can produce floods.

A Cold Drop is formed when three events coincide: warm sea, unstable surface atmosphere and cold air aloft. When the sea is located at high temperaturesIt gives off a lot of water vapour. If in this situation a squall or cold front arrives and there is a cold air pocket at altitude, a situation of instability of the surface air is produced, which increases as we ascend. The water vapour released by the sea in large quantities, rises in the wake of instability and condenses as it meets the cold zone, clouds forming which can enlarge at high speed due to the ease with which the rising vapour can rise upwards. until it encounters colder areas and, in this way, becoming more and more condensed water. This means that in a very few hours, water can form large storm clouds.

The Gota Fria produces extraordinarily violent (but short-lived) showers and storms that normally affect a small area. They are frequent in the coastal areas of the Mediterranean, especially between September and October.

How does the cold drop affect the grass?

The golf courses (especially those in the coastal area of the Mediterranean) can be seen affected This is why it is necessary to take into account the possible effects of this meteorological event. destruction that may be caused by them (such as falling trees, flooding of certain areas, problems in the terrain, etc.).

Impacts on Agriculture and Lawn Care

This type of heavy rainfall can have the following effects on turf:

• Floods and erosion: Heavy rains can cause flash flooding and soil erosion, which adversely affects both crops and grass fields, leading to loss of essential nutrients and structural damage to the soil.
• Displacement: Heavy rains can displace the turf, which can lead to bald patches.
• Diseases: Excessive humidity favours the appearance of fungal diseases and other turf-related problems such as root rot and moss growth.

Where are the cold drops produced?

Cold drops are a meteorological phenomenon that mainly occurs in regions with climatic conditions and geographic areas. The most affected areas and their characteristics are summarised here:

1. Mediterranean and Southern Europe: Includes Spain, Italy, Greece and southern France. The combination of cold air at high altitude and warm waters from the Mediterranean favours the formation of cold drops, especially in autumn, causing heavy rain and thunderstorms.
2. Southwestern United States: In areas such as California, Arizona and New Mexico, the interaction of cold Pacific air with warm, dry desert air can generate cold drops, resulting in sudden heavy rainfall.
3. South American coasts: Particularly in Chile and Peru, where cold air at high altitude meets warm air from the Pacific, causing unusual precipitation.
4. Eastern Australia: In regions such as Queensland and New South Wales, the cold drop is formed by the collision between warm, moist Pacific air and cold air masses, causing severe thunderstorms.

In these regions, cold drop is characterised by the rapid formation of heavy rainfall and storms, often with severe consequences such as flooding. The phenomenon is most common during seasonal changes, especially from summer to autumn.

How to mitigate the effects of the cold drop? 

Prevention strategies Early Warning Systems

Having a weather station is the perfect tool to know both the environmental humidity and all the necessary variables for an adequate management of the field in order to foresee possible harmful consequences.

Technology and Preparedness - Cold Drop Contingency Plans

Contingency plans are crucial to mitigate the impacts of cold drop on agriculture and turf care. These should be tailored to the specific characteristics of each area and type of crop or turf:

• Risk Assessment and Infrastructure Improvements: Conduct risk assessments before the rainy season and reinforce structures such as dykes and drainage systems. In high-risk areas, consider temporary or permanent flood barriers.
• Water Evacuation Systems and Protection of Green Areas: Design efficient drainage systems and use protective covers for small areas. On golf courses, prepare soil mixtures that promote rapid drainage.
• Chemical and Fertiliser Management: Store these materials in safe places to avoid dispersal during flooding.
• Communication, Training and Documentation: Maintain clear communication with staff, conduct training and drills, and ensure that insurance policies are up to date.
• Post-Event Evaluation: After a cold drop event, it is important to quickly assess the damage and start recovery work, including infrastructure repair and review of drainage strategies.

Cold drop presents significant challenges, but with proper planning and the implementation of effective strategies such as early warning systemsmitigating their effects is possible. Collaboration between agronomists, greenkeepers, farmers and scientists is vital to develop innovative and sustainable solutions.