A MAN RUNS down an icy path to return to his loved ones. A family gathers together inside to escape the chilly weather. A carol singer braves the cold to spread some festive warmth. As anyone who has watched “Holiday Inn” (1942), or “It’s a Wonderful Life” (1946), or “White Christmas” (1954), or “Home Alone” (1990), or “The Holiday” (2006) knows, snow is integral to a festive film. But in Los Angeles, where a lot of movies are still made, snow hasn’t fallen since January 1962. Creating realistic snow banks, icicles, frosting and drifting flakes has long posed a challenge to film-makers. Necessity has been the mother of invention.

In the early days of Hollywood, special-effects artists made snow out of commonplace materials. Balls of cotton wool were teased into fluffy piles–a fire hazard, given their flammability and the hot studio lights. Indigestion tablets were ground into a fine powder and blown by large fans to mimic snow storms (actors soon complained that ingesting the dust was affecting their health). Cornflakes were painted white, which looked convincing on screen but had some annoying drawbacks for directors making “talkies”. The sound of crunching cornflakes underfoot made dialogue unuseable, and it would have to be redubbed.

A much graver hazard was posed by the substitute used in “The Wizard of Oz” (1939). Dorothy is awoken from her sleep in a poppy field by falling snow—actually industrial-grade chrysotile, commonly known as asbestos, and highly carcinogenic. Marketed under such names as “Pure White”, asbestos was used in movies until after the second world war, and was commonly sold as a form of Christmas decoration. Around 1,000 pounds (453 kilograms) of asbestos was used on the set of “The Country Doctor” (1936) to mimic the wilds of Quebec, Canada.

Frank Capra objected to these methods not because of concern for his crew’s health, but because they were too noisy, and Capra wanted to record the dialogue for “It’s a Wonderful Life” (1946, pictured) live. Russell Shearman, the special-effects supervisor on the film, came up with a new idea: foamite, the fire-suppressant foam found in fire extinguishers. He mixed it with water, sugar and soap, and sprayed 6,000 gallons of the mixture in front of high-powered fans to cover the set. The artificial snow looked realistic and, crucially, was quiet to walk on. (That year Shearman won the Technical Achievement Award at the Oscars for his efforts.)

When adapting “Doctor Zhivago” for the screen in 1965, David Lean had to chart an affair which takes its lovers across the frozen plains of Russia. He was unable to film on the real steppe described in Boris Pasternak’s novel, as the book was banned in the Soviet Union. So the film was mostly made in the countryside outside Madrid instead (some sequences were shot in Finland), where a combination of frozen beeswax and ground marble provided the impression of ice and deep snow.

Filming on location with real snow is an option, but an expensive and unpredictable one. The opening scene of Charlie Chaplin’s “The Gold Rush” (1925) is a spectacular shot of the Sierra Nevada mountain range in California (standing in for the Chilkoot Pass in Alaska), but the glacial conditions were not conducive to comedy. Chaplin soon retreated to the comfort of the studio, where a snowy landscape was made with flour and salt. Later, Stanley Kubrick’s famously meticulous methods prohibited him from working with the real stuff: actual snow would have melted before the first, perfected scene was in the can. The chilly horror of “The Shining” (1980) was recreated in a studio in Britain using crushed styrofoam and salt. More recently, Alejandro Iñárritu sought to film “The Revenant” (2015) in natural light on location. He had hoped to work entirely in Canada, but the weather there was unseasonably warm and production had to move to Argentina to shoot the final scenes.

Today, recycled paper (known as “Snowcel”) often does the job. The product has been used in films such as “The Day After Tomorrow” (2004) and “Gladiator” (2000); the material’s only drawback is its tendency to defy gravity and drift upwards. Increasingly, computer-generated imagery (CGI), or visual effects, supplements or replaces these substances, even in live-action movies. Although snow, like fire and fur, is difficult to get right, new techniques were developed for “Frozen” in 2013. Animators employed a “Material Point Method”, using algorithms to track and recreate the properties of snowflakes, even simulating different kinds of snow. Who needs to dream of a white Christmas when you can conjure it with a keyboard?