UK Power Networks officials said up to 270,000 homes were without power. Flood alerts were issued for many parts of southern England and emergency officials said hundreds of trees were knocked down by gusts.
London's Heathrow Airport, Europe's busiest, cancelled at least 130 flights and express trains between central London and Gatwick and Stansted airports were suspended. Huge waves prompted the major English port of Dover to close, cutting off ferry services to France.
A nuclear power station in Kent, southern England, automatically shut its two reactors after storm debris reduced its incoming power supply. Officials at the Dungeness B plant said the reactors had shut down safely and would be brought back online once power was restored.
In central London, a huge building crane near the prime minister's office crumpled in the gusts.
Thousands of homes in northwestern France also lost electricity, while in the Netherlands several rail lines shut down, airport delays were reported. Dutch citizens were warned against riding their bicycles — a favored form of transport — because of the high winds, and Amsterdam's central railway station was shut down by storm damage.
Some English rail lines also closed Monday morning, and some roads were closed due to fallen trees and power lines. There were severe delays on many parts of the London Underground and London Overground trains were delayed several hours.
In Britain, police said a 17-year-old girl in Kent and a man in his 50s in Watford were killed after trees fell on her home and his car. A London man died in an apparent gas explosion at his home and a teenage boy drowned Sunday while playing in the surf at Newhaven.
Amsterdam police said a woman was killed by a falling tree and German authorities said two others were killed when a tree fell on their car in Gelsenkirchen, western Germany.
A stretch of the A71 autobahn in the central German state of Thuringia was closed because of winds gusting up to 100 kph (62 mph).
The storm has hurricane-force gusts but is not classified as a hurricane since it did not form over warm expanses of open ocean like the hurricanes that batter the Caribbean and the eastern United States, according to Britain's national weather service, the Met Office.
Britain does not get hurricanes because hurricanes are "warm latitude" storms that draw their energy from seas far warmer than the North Atlantic, the agency said.
The storm is not named and does not have an "eye" at its center as hurricanes typically do. On social networks it has been called stormageddon.
Sweden's Meteorological Institute upgraded its advisory Monday, warning that a "class 3" storm that could pose "great danger to the public" as it hits western and southern Sweden in the evening.