Rain in the Doha desert: the 2009 Qatar MotoGP

On this day in 2009, the first round of the Motorcycle Grand Prix season had to be suspended. Racing became impossible after after a rare and dramatic rain event at the 5.38km Losail Circuit, north of Doha, the capital of Quatar. The track was purpose-built and only five years old, but races were held during the night under floodlights. This was intended to counter sweltering daytime temperatures and to cater for the European audience, but wet races under lights face the extra safety issue of glare off the track.

The 125cc race began, but only three laps in, heavy rain began to fall, and in lap four the race was called off completely. The rain had stopped and the track had begun to dry out in time for the 250cc race, which continued as normal although shorter, so when the time came for the main MotoGP race track conditions were greatly improved.

Qatar MotoGP Motorcycle Racing

Unfortunately, just as the formation lap was about to start, more rain fell. This time the rainfall was intense, with dramatic thunder and lightening. After negotiations, it was decided that the race would have to be called off and re-run the following day in hopes of better weather. The Monday race went without a hitch, and 1st place went to Casey Stoner (Ducati), who led by a comfortable margin from start to finish.

The city of Doha has a hot desert climate, with exceptionally high temperatures all year round. Average daily temperature peaks at 34.7°C in July, and there is no record of the city ever seeing temperatures below zero during the day. The rainiest month is January with 13.2 mm in total (on average), compared with Birmingham’s 66.2mm. In the average April, there are just 1.4 days of rain.

temps

Officially, a thunderstorm is simply a storm which contains lightening and thunder, which is the accoustic effect of the lightening on the atmosphere. These are often accompanied by strong winds and heavy rain, although no rain at all is also possible. The key ingredients for thunderstorms are rapid uplift and warm, moist air, both of which can be found in abundance in Qatar.

On the day of the motoGP, incoming solar radiation had been heating the surface air, with a relative humidity of around 50% (which means that the air has about half as much water vapour as it could possibly hold). As we all know, warm air rises, but as it increases in altitude it is cooled. This means that the amount of moisture one “parcel” of air could hold reduces and some of the liquid condenses out to form cumulonimbus clouds, which can be up to 20km from top to bottom.

precip

Because the cloud is so deep, there is lots of potential for turbulence as the water droplets move up and down inside the cloud, until they eventually become too big and gravity pulls them down. The droplets in thunderstorms are some of the biggest produced, which is why they can cause flash flooding.

Since it only rains an average of nine days a year at the track, the teams and drivers were very unlucky to see two races affected by rain.

Have you ever been caught in a thunderstorm?

Here’s a good video to get a feel for the intensity of rainfall: https://www.youtube.com/watch?v=Rbvmj_9Cu_4

My thanks to Darren Hale for the suggestion of this topic.

03motogp