Two climbers died on Mount Snowdon in Wales and three people were killed in accidents and from the cold in Italy.
London lay under 10 centimetres (four inches) of snow, the most recorded in the British capital in 18 years. The storms also hit France and Spain, closing roads and rail tracks, and spread as far south as Morocco.
A Cyprus Airways plane with 104 passengers came off the icy taxiway at Heathrow, the world's busiest international airport, airport operator BAA said. No injuries were reported.
Both runways were temporarily closed, however, and Heathrow halted all flights for several hours. A number of other British airports were closed or had cancellations and severe delays.
British Airways called off all short-haul flights for the day, although a spokeswoman said the airline hoped to operate about 20 long-haul flights, including to the United States, Asia and Africa, on Monday evening.
She said BA had booked 2,500 hotel rooms in and around London for people who were stranded.
Eurostar advised passengers against travelling between London and Paris on high-speed trains because of snow delays.
British regional trains were badly hit and London subway and bus services at one point came to a near standstill.
The government was doing "everything in our power," to make sure transport systems ran smoothly, Prime Minister Gordon Brown said.
Thousands of schools closed around the country and an army of snow ploughs and gritters worked to clear roads, many of which saw gridlock despite a warning from the British Highways Agency against all but essential travel.
"It's absolute madness going in to work, but at least I can say I tried," said Bree McWilliam, an Australian policy analyst who experienced her first ever snowfall as she struggled into work.
London Mayor Boris Johnson offered temporary respite for drivers, announcing the city's eight-pound (€8.8, $11.3) daily congestion charge for driving into central London was suspended for the day.
The snowfall even forced football chiefs in England to extend the strict window imposed to allow clubs to sign or transfer players beyond the 1700 GMT deadline.
Italy faced grimmer news, with three people killed by the cold and torrential rainstorms. One man died from the cold in the northern town of Lecco. Another was killed in Sicily when his car was swept away by a river.
Another 500 people were evacuated from their homes in Cosenza in the southern region of Calabria. Snow also forced the cancellation of about 20 flights from Rome and Milan.
In France, Paris-Charles de Gaulle airport cancelled at least 87 flights and others were delayed. Paris-Orly also reported delays, although both were getting back to normal by mid-evening.
Some French high-speed trains were cancelled and those that did run were ordered to slow. France's roads agency also urged motorists to cancel non-essential journeys, with some roads impassable around Paris and in the east around Strasbourg, where dozens of accidents were reported.
Snow and heavy rain were forecast for different parts of France on Tuesday.
Up to 20 centimetres of snow also fell in parts of Switzerland, with part of the road around the San Bernardino tunnel was closed.
In Belgium, about 400 kilometres (250 miles) of traffic jams were reported during the morning rush hour around Brussels and other main cities.
Snowfalls also snarled traffic in several parts of Spain including the Madrid area where two highways were temporarily closed, the National Travel Administration Department (DGT) reported.
A storm packing winds of more than 100 kilometres (60 miles) an hour injured about a dozen people in southern Spain, emergency services said.
In the Mediterranean port of Malaga, winds ripped off part of the roof from the city's main bus station. Four people were injured, including one in a serious condition.
At Estepona, near Marbella, the storm knocked down a circus tent during a performance Sunday night, slightly injuring five members of the public.
In Ireland, snow caused hazardous driving conditions and flights to Britain were disrupted with heavy snowfall expected later Monday.