The 'Collide' singer barricaded herself in her Hackney home as civil unrest broke out in the borough after the shooting of Mark Duggan by police during an attempted arrest in Tottenham.
Speaking on the first anniversary of the riots, which also occurred in other major cities nationwide, Lewis told The Sun: "I was worried about what would happen to the people who had their businesses and homes damaged.
"My parents both live in Hackney too and my dad was supposed to bring a CD round to my house that night. He rang me and said, 'How badly do you want this CD, because I've just seen a Mini (car) get a petrol bomb thrown at it?' I told him to go home straight away.
"The pictures on the news and in the papers were terrifying and it just kept rolling on. Seeing the pictures of the violence, looting and rioting made you think it was just totally out of control and the police were overwhelmed."
Lewis previously blamed the riots on "hoodrats getting totally out of control", saying: "I don't think there was any motivation behind it other than to cause trouble 'cos they're bored and want free stuff."
Watch Leona Lewis singing 'Collide' below: