Flash Flood Warning in Coconino County, Arizona Through August 10 at 5:45 PM MST: Which Roads to Avoid and When It Is Safe to Move

A Flash Flood Warning is in effect for Coconino County, Arizona, issued by the National Weather Service Flagstaff, Arizona office. The warning runs from 2:52 PM MST on August 10, 2026, through 5:45 PM MST on August 10, 2026. If you are reading this during that window, the threat is active. If you are reading this after 5:45 PM MST, check the NWS Flagstaff page directly to confirm whether the warning has been extended, downgraded, or allowed to expire.

Coconino County covers a large stretch of northern Arizona, including the Flagstaff area and surrounding communities. The combination of monsoon moisture and terrain in this region makes flash flooding a recurring and fast-moving hazard, capable of turning a dry wash into a dangerous torrent within minutes of a storm cell moving overhead.

What NWS Is Telling Residents and Drivers Right Now

The National Weather Service has made the hazard picture specific and actionable. According to the official warning text, flooding of washes and creeks will occur. Beyond the natural drainage channels, the alert explicitly flags two road hazard categories that affect every driver in the area.

First, dirt roads: the NWS states that some dirt roads will become muddy and impassable. If your route home, to a trailhead, or to a rural property relies on an unpaved road, treat it as potentially blocked or dangerous for the duration of this warning. Attempting to drive a dirt road that has become saturated risks getting a vehicle stuck in mud far from assistance, at a time when emergency resources may be stretched across the county.

Second, and critically, the alert does not limit its road hazard language to unpaved surfaces. The NWS warning states that paved roads and underpasses could become flooded as well. This matters because drivers often assume a paved surface is a safe surface during a flood event. Underpasses in particular collect water quickly and offer no escape if a vehicle stalls. The warning makes no distinction between rural back roads and in-town paved streets: both are named as at risk.

The direct, practical guidance the alert implies is straightforward: do not drive into flooded roadways or underpasses, do not attempt dirt roads during the warning window, and stay away from washes and creek banks until the warning has expired and water levels have receded. Water depth on a flooded road is almost always impossible to judge accurately from a driver’s seat.

How This Fits the Broader Fire and Flood Season in Arizona

Northern Arizona sits in a landscape shaped by both wildfire and monsoon flooding, and the two hazards are directly connected. Fire activity across the region over recent seasons has stripped vegetation from hillsides and burned away the ground cover that would otherwise slow and absorb rainfall. When monsoon storms move over burned terrain, water moves faster, carries more sediment, and reaches roads and structures sooner than it would in an unburned watershed. Coconino County has experienced both significant fire years and significant flood years, sometimes within the same season. For residents of the region, preparedness is not a single-event exercise. Knowing which roads in your area are dirt, which underpasses flood first, and where local washes run is the kind of location-specific knowledge that makes the difference between a minor inconvenience and a genuine emergency. Our evergreen flash flood preparedness guide covers how to build that local picture before the next warning is issued.

For official updates, monitor the National Weather Service Flagstaff, Arizona office at weather.gov. This warning expires at 5:45 PM MST on August 10, 2026, but conditions can change. Verify current status before traveling in Coconino County.

For the fundamentals that apply beyond this specific alert, see our Flood Preparedness guide.

Source: National Weather Service (NWS Flagstaff AZ). Active alert data retrieved 2026-08-10 22:01 UTC via api.weather.gov.