A helmetless couple riding an ATV in northeast Calgary are in hospital Monday after a weekend crash.

Calgary police said the male driver, 36, and the female passenger, 26, were riding the ATV at about 2 a.m. on Sunday in a residential area. The operator lost control and rolled the ATV in a turn, throwing both of them into a fence.

The female passenger suffered life-threatening injuries. The man was reported to be in stable condition.

Police said alcohol appears to be a contributing factor in the accident.