The Cataclysm was an apocalyptic event (which occurred in 2027) that decimated the world; destroying mortals and a wide majority of the magical community, leaving only a few survivors. Not only destroying lives, but the Cataclysm also damaged many of the planes, including the Heavens and the Underworld. The effects of the Cataclysm have shown to be neutral, showing no particular bias to who it targeted, as both Demons and good magical beings were destroyed. It is still unknown to what caused the Cataclysm.
The Cataclysm also had effects on people's powers. Due to the destruction of the Heavens, all orbing abilities were darkened so instead of white and blue orbs, beings like Wyatt and Paige orb with black and dark blue orbs. Chris' access to the Vitalium Vitalis spell was also disconnected after the Cataclysm.
There are only very few of those whom survived the Cataclysm; those known are listed below.
Wyatt was the only magical being to have survived the Cataclysm due to his own shear strength; it was due to Wyatt being so powerful that allowed him to survive the disastrous event completely unharmed; even though it wiped out his family.
Paige was extremely lucky in surviving the Cataclysm, and was the only Charmed One to survive. As the Cataclysm began, Paige orbed from the Manor, whilst teleporting she was traveling through the Neutral plane which was left untouched - as she materialized, everything around her was gone, including her family.
It remains unknown as to how Ava survived the Cataclysm, however it didn't leave her untouched. The Cataclysm is known for turning the once nice Gypsie into an evil being, trying to covert her own coven to turn against the good witches.
Tyler was able to cocoon himself and tear through the Cataclysm with his Pyrokinetic ability; this is a very clear example of how powerful Tyler is. Tyler was still hurt during the cataclysm, but was able to heal over time.
With the use of his Astrakinesis, Nick was able to phase into the Astral plane which remained untouched by the Cataclysm. He remained in the Astral plane for sometime due to not knowing when it would be safe to teleport out.
Jasmine was able to survive the Cataclysm with the use of her powers. She was able to sense the movement of the destruction and was able to force herself deep enough into the earth to be safe from the Cataclysm.
Violet barely survived the Cataclysm; she used her ability of Gravity Manipulation to suspend the cataclysm above her, she was still hit and critically injured. She was rescued by Ava, explaining her allegiance to her.
Zachary survived the cataclysm due to his enhanced Rapid Regeneration caused by the spell cast during his teen years. After his survival, he sought out the Charmed Ones but after finding they had perished, he found Parker Halliwell and Lilian Jenkins in the remains of the Manor.
The duo survived the Cataclysm thanks to the Book of Shadows. As the cataclysm reached the boys, the Book conjured a shield which saved them from alot of damage, but not all of it. Chris and Sam were both fatally wounded, but were saved by Paige Matthews.
The two were together in the basement of the Halliwell Manor during the events of the Cataclysm, for current unknown reason the basement of the Manor was the only section of the house to remain untouched - as well as the two inside.