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Avoid Flash Flooding

Flash floods are common during heavy rains, particularly when preceded by either:

1. Excessively dry periods, which bake the dirt of the high plateaus like a clay pot, creating an impervious layer of thick, hard soil. When heavy rains hit this hard crust, the water does not soak into the soil, but instead runs off quickly down-stream to create raging creeks and rivers.

OR

2. After 2-3 days of rain, when the plateau soil becomes saturated and can no longer soak up water. Excess rain then quickly runs into the streams and rivers, sometimes building to dangerous proportions. These heavy rainstorms usually occur in July-September, but it is not uncommon for storms to drop significant rain any month of the year and cause the river to rise very quickly.


The actual "flash," or sudden build up of water, rocks, logs and other debris, may force a wave of water to come rushing through a narrow canyon like Orderville, then junction with excessive run-off in the Wall Street corridor of the Narrows, causing a "roll-through." This roll-thru carries a high density of debris and is deadly. The above images were taken in Zion by a Ranger where Oak Creek Canyon merges with the Virgin River. The accumulated effect of side canyon debris concurrently meeting already rising waters creates a highly dense water flow, unhikable and unswim-able.

Because flash floods are somewhat unpredictable, Zion National Park does not guarantee your safety even on the sunniest day of the year. Occasionally, however, the Park will post closure signs at the Temple of Sinawava to discourage visitors from hiking beyond the end of the Riverside Walk. We can assure you, if the Park has posted the Narrows as CLOSED, do not hike into the river.

Stop by Zion Adventure Company any time for a free flash flood clinic, where we will expand upon the following points: