|Formed||December 7, 2011|
|Dissipated||December 11, 2011|
|Highest winds||165 mph (265 km/h)|
|Lowest pressure||957 mbar|
$157 million (2011 USD)
|Areas affected||Scotland, Northern Ireland, England, Wales, Ireland, Netherlands and Scandinavia|
Cyclone Friedhelm was a major European windstorm which caused a lot of damage in the United Kingdom, leaving 50,000 people without power and damaging many areas with winds the strength of a Category 5 hurricane: 165 mph (265 km/h). In populated areas hurricane-force winds of up to 80 mph (130 km/h) were reported, with damaging gusts of 105 mph (170 km/h). It was the worst storm to affect Scotland in ten years.
At 0000 UTC on December 8, 2011, the Met Office noticed a strong low pressure system, along a polar front to the west of Scotland. The polar front supported multiple cold fronts moving towards mainland Europe from the Atlantic Ocean, as well as an eastward-moving warm front approaching the British Isles. When the fronts joined with eachother, an extremely tight area of pressure gradient developed a large area of high winds. Due to the high temperature gradient between the fronts, the cyclone entered a phase of rapid deepening. By 0800 UTC, the cyclone reached a pressure of 977 mbar, bringing gale-force winds to much of the British Isles. The pressure dropped to a record 957 mbar at around 1200 UTC, causing high gusts of 105 mph (170 km/h) to be observed at the surface. A maximum wind speed of 165 mph (265 km/h) was reported on a mountain in the region of Aberdeenshire. Due to the pressure dropping by 20 mbar (hPa) and the high winds, scientists reffered the storm as a weather bomb. A FAMM aircraft intercepted the storm on several occasions, studying its pressure, temperature, winds and humidity.
On December 7, the Met Office issued its highest warning: Red, for the Central Belt of Scotland. This was the first time that the Met Office had to issue a red warning for any part of the British Isles. They advised the public to take action and listen to police. By 0800 UTC on December 8, all schools in west Scotland have been closed, and by 1200 UTC, schools in Edinburgh and the east coast have been closed.