MADRID, Jan 9 — Four people died in Spain as Storm Filomena caused travel chaos across the country, blanketing Madrid in the heaviest snowfall in decades and forcing authorities to mobilise troops to rescue trapped motorists.

Rescue services reached 1,500 people trapped in cars, while skiers glided down Gran Via, normally one of the busiest streets in the capital. Other Madrid residents used the freak blizzard to snowboard down the road or pelt each other with snowballs.

A man and woman who were traveling in a car drowned after a river burst its banks near Malaga, southern Spain, and two homeless people froze to death, one in Madrid and the other in the eastern city of Calatayud, authorities said.

Responding to the events, King Felipe VI and Queen Letizia tweeted: "The royal family would like to express their sorrow for victims of the storm ... and ask for extreme caution against the risks of accumulation of ice and snow.”

Interior minister Fernando Grande-Marlaska urged Spaniards to avoid all but essential travel. "We are facing the most intense storm in the last 50 years,” he said.

More than 650 roads were blocked by snow, said Grande-Marlaska, leaving some drivers stuck in their cars from last night until today.

Patricia Manzanares, trapped in her car on the M-40 motorway in Madrid since 7 p.m.yesterday, told RTVE television: "I have been stuck here without water or any other help”.

Aena, which controls the country's airports, said Madrid's Barajas airport, which was closed on Friday night, would remain shut for the rest of today. It said at least 50 flights to Madrid, Malaga, Tenerife and Ceuta, a Spanish territory in North Africa, were cancelled.

The State Meteorological Agency said it was the heaviest snowfall in Madrid since 1971, while José Miguel Viñas, a meteorologist from Spanish National Radio, said that between 25 cm and 50 cm had fallen in the capital, which he said made it the largest snowfall since 1963.

Atletico Madrid's game against Athletic Bilbao, scheduled to kick off at 1515 GMT today, was postponed, La Liga said in a statement. — Reuters