Avalanche is the name of two fictional characters appearing in American comic books published by Marvel Comics. Each character is usually depicted as an enemy of the X-Men.

The Dominikos Petrakis version of Avalanche is a Cretan mutant who possesses the ability to generate seismic waves from his hands that are strong enough to create earthquakes of varying sizes and to disintegrate any substance other than living tissue. He has been a member of the Brotherhood of Mutants and Freedom Force.

The animated series X-Men: Evolution portrays a different version of Avalanche named Lance Alvers, a misguided mutant teenager and romantic love interest of the X-Men's Shadowcat.

Created by writer Chris Claremont and artist/co-writer John Byrne, the Dominikos Petrakis version of Avalanche first appeared in The Uncanny X-Men #141 (Jan. 1981).

Avalanche's story before Mystique recruits him for the second Brotherhood of Evil Mutants is largely a mystery. It is known, however, that he is an immigrant from the Greek island of Crete. There, he lives a quiet life until Mystique invites him to join her new Brotherhood. During his first public appearance with the Brotherhood, the team unsuccessfully attempts to assassinate Senator Robert Kelly during his hearings and testimony on his belief that mutants pose a mortal threat to humanity. The X-Men arrive to stop the assassination and battle the new Brotherhood. After escaping the fray, Avalanche continues his support of Mutant supremacy via terrorist and criminal activities and battling the Avengers with the Brotherhood.

Avalanche briefly leaves the Brotherhood and attempts to blackmail the state of California into paying him an enormous sum to prevent him from using his power to generate an earthquake. Avalanche fights the Hulk alongside Landslide on this occasion and suffers broken arms when he attempts to use his powers against the Hulk. When he returns to the Brotherhood, together they encounter Rom the Space Knight and Hybrid. The team later battles the X-Men as the "Brotherhood of Evil Mutants" one final time.

After that, The Brotherhood's leader Mystique offers the group's services to the United States government. Their first mission under their new name of Freedom Force is to capture the mutant Magneto on behalf of the federal government. The government then sends Freedom Force to capture the Avengers. While seeking to arrest Rusty Collins, he clashed with X-Factor. Freedom Force then fights the X-Men in Dallas and is present at the X-Men's apparent demise, and battles the New Mutants in Dallas as well. Freedom Force then battled Cyclops and Marvel Girl. Freedom Force again tries to arrest Rusty Collins and battled the New Mutants, but are able to arrest Rusty and Skids as well. They are also dispatched to rescue Robert Kelly from a South American drug syndicate that had kidnapped him, battling the syndicate's superhuman agents in the process. Freedom Force also has a costly battle with the Reavers on Muir Island where a number of members are killed or seriously injured. During the Acts of Vengeance, Avalanche teams with Blob and Pyro against the Avengers. Avalanche then joins Freedom Force's effort to stop a prison breakout at the Vault. Avalanche then participates in Freedom Force's final mission in Kuwait. He abandons Blob and Pyro during the battle with Desert Sword to save the seriously injured Crimson Commando.

When Freedom Force is disbanded after the botched mission in the Gulf War, Avalanche continues to work for the government as part of Project Wideawake, but soon leaves when he finds out that his friend Pyro had contracted the Legacy Virus.