What is cloud seeding and did it cause the floods in Dubai?

Clouds from around a ‘condensation nuclei’.

Clouds form when a parcel of air becomes saturated and unable to hold anymore invisible water vapour so cools and condenses into visible water droplets and at higher and colder levels into ice crystals.

Air can become saturated in two ways: condensation or evaporation. The most common way is that as air rises it expands due to lower atmospheric pressure and the energy used in expansion causes the air to cool until it reaches its dew point and condensation occurs. Generally speaking, for each 100 metres which the air rises, it will cool by 1°C.

The parcel is become of air can also become saturate by increase the amount of water content in the air through evaporation until it reach a point where it can not contain anymore water vapour .

For clouds to form though, they need a ‘condensation nuclei’ to form around and this is usually a tiny particle of dust or salt floating in the atmosphere. Without these particles, raindrops or snowflakes cannot form and precipitation won’t occur.

What is cloud seeding?

Cloud seeding involves manipulating clouds so that they rain or produce more rain. (Or snow if at higher altitudes and colder climates). This is done by introducing more condensation nuclei for clouds to form around. A common method is to use an aircraft to drop small particles, such as silver iodide, into the clouds so that the water vapour condenses around these more easily and turns into rain. Silver iodide exists naturally in the environment at low concentrations and is not known to be harmful to humans or wildlife.

This technique is used all over the world as a method of enhancing winter snowfall and the UAE has used it in recent years to help address water shortages.

Was cloud seeding to blame for the Dubai flood ?

Earlier this month a storm hit Dubai with some areas recording more than 250mm of rain in less than 24 hours which is the largest ever recorded in a 24 hour period since records began and over double their yearly average of around 97mm. Dubai’s International Airport was forced to close with hundreds of flights cancelled and at least 20 people died in Oman and 4 in the United Arab Emirates.

More than 250 mm is fell of rain fall in less than 24 hour .

Videos went viral on social media attributing the flooding to cloud seeding however, scientists have concluded that cloud seeding did not have a ‘significant influence’ on the flooding.

A ‘cut off’ low pressure system was instead the main cause and this drew in moist, warm air which blocked other weather systems from forming and had become detached from the upper level flow and remained stationary for longer.