The Virgin River has carved a spectacular gorge in the upper reaches of Zion Canyon: 16 miles long, up to 1,000 feet deep, and at times only 30 feet wide. Walking in the shadow of soaring walls, sandstone grottos, natural springs, and hanging gardens can be an unforgettable wilderness experience. It is not, however, a trip to be underestimated. When hiking through the Virgin River Narrows, at least 80% of the route is spent wading, walking, and swimming sections of the river. There is no maintained trail; the river is the route. The river current is swift, the water is cold, and the rocks underfoot are slippery. Flash flooding and hypothermia are constant dangers. Per NPS