Yavapai Flash Flood Warning Held Until 4:45 AM After Granite Creek Surge

TL;DR: Prescott-area flash flooding continued after Granite Creek surged 4 feet

TL;DR: The National Weather Service in Flagstaff kept a flash flood warning for Yavapai County in effect until 4:45 AM MST on September 29, 2026, after a gauge on Granite Creek near Prescott recorded a rapid 4-foot rise and warned that life-threatening flooding was likely still ongoing.

According to the FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 445 AM MST EARLY THIS MORNING FOR YAVAPAI COUNTY, issued by NWS Flagstaff AZ for Yavapai County, AZ, the overnight warning covered the Prescott and Chino Valley area. The bulletin was posted as 9/29/2026 · 6:32:13 AM EDT on the Forth National Weather Service feed. A second same-day bulletin from the same office, Flash Flood Warning issued September 29 at 12:44PM MST until September 29 at 5:00PM MST by NWS Flagstaff AZ, extended a separate flash flood warning for the Paria River in Coconino County until 5:00 PM MST.

Overnight Yavapai warning stayed active until 4:45 AM MST

The Yavapai County warning remained in effect until 4:45 AM MST early in the morning. That continuation status meant households in the warned area were still under a formal flash flood warning during the pre-dawn hours rather than an expired or downgraded advisory.

The warning applied to Yavapai County, AZ. It was issued by NWS Flagstaff AZ. The office identified the event as a flash flood warning, not a watch or lesser statement.

For preparedness planning, the key time window was the overnight period leading into 4:45 AM MST. Residents who checked conditions late at night would still have found the warning active. Anyone traveling before sunrise needed to treat low crossings, washes, and underpasses as potentially flooded.

Granite Creek gauge showed rapid 4-foot rise near Prescott

At 3:27 AM MST, the Granite Creek river gauge near Prescott had started to decline. The decline followed a rapid 4-foot rise tied to thunderstorms producing heavy rain around 1:52 AM MST.

The sequence matters for households. Heavy rain developed around 1:52 AM MST. The creek rose rapidly by 4 feet. By 3:27 AM MST, the gauge reading had begun to fall. Despite that fall, the bulletin stated that flash flooding was likely still ongoing.

That pattern — rain, sharp river rise, then a gauge decline while flooding continues — is common in small, fast-responding desert and mountain drainages. Water can remain high in side channels, road dips, parks, and downstream reaches after the upstream gauge crest passes. The warning therefore continued until 4:45 AM MST.

Hazard was described as life-threatening flash flooding

The listed hazard was life-threatening flash flooding, with thunderstorms producing flash flooding. The listed source was river gauge reported.

The expected impact was life-threatening flash flooding of creeks and streams, normally dry washes, urban areas, highways, streets and underpasses. That wording covered both natural channels and built infrastructure.

The bulletin added that flooding of washes and creeks will occur. It stated that some dirt roads will become muddy and impassable. It also stated that paved roads and underpasses could become flooded as well.

For a household, those three outcomes define the overnight risk: natural channels flooding, dirt access routes losing passability, and hard-surface roads and underpasses taking water. The warning did not limit the threat to rural ground alone because urban areas, highways, streets and underpasses were named in the impact statement.

Neighborhoods and community sites named in the warning

The warning listed locations that will experience flash flooding. The named places were Chino Valley, Prescott, Prescott Regional Airport, Embry-Riddle Aeronautical University, Willow Creek Reservoir, Watson Lake, Downtown Prescott, Jim McCasland Willow Creek Park, Watson Lake Park, Whipple, AC Williams Granite Creek Park, Courthouse Plaza and Acker Park.

Chino Valley and Prescott anchored the community footprint. Downtown Prescott, Courthouse Plaza and Whipple placed the threat in the central built area. Prescott Regional Airport and Embry-Riddle Aeronautical University placed aviation and campus facilities inside the warned zone.

Willow Creek Reservoir and Watson Lake placed standing-water recreation sites inside the area of concern. Jim McCasland Willow Creek Park, Watson Lake Park, AC Williams Granite Creek Park and Acker Park placed neighborhood and creekside parks inside the area where flooding was expected.

Households near those parks and reservoirs needed to avoid creek edges, low trails, parking aprons near washes, and crossings that collect runoff. Travel to or from the airport and university area during the warning window called for checking road and underpass conditions first.

Highways flagged: State Route 69, State Route 89 and State Route 89A

The bulletin named specific highway segments. It listed State Route 69 near mile marker 296. It listed State Route 89 between mile markers 310 and 320. It listed State Route 89A between mile markers 318 and 319.

Those mile-marker ranges give drivers concrete checkpoints. A trip that used State Route 69 near mile marker 296 fell inside the named highway exposure. Travel along State Route 89 between mile markers 310 and 320 fell inside the named exposure. The short State Route 89A section between mile markers 318 and 319 was also named.

Because the impact statement included highways, streets and underpasses, a paved highway was not treated as automatically safe during the warning. The bulletin separately warned that paved roads and underpasses could become flooded. Dirt-road users faced a different failure mode, with some dirt roads becoming muddy and impassable.

Creeks, washes and rivers placed at risk

The Yavapai bulletin listed the following creeks, washes and rivers: Verde River, Bottleneck Wash, Bannon Creek, Granite Creek, Little Chino Valley, Willow Creek and Miller Creek.

Granite Creek was the channel with the measured 4-foot rapid rise near Prescott. Willow Creek connects to the named reservoir and park ground. Bannon Creek and Miller Creek add smaller tributaries where water can rise quickly. Bottleneck Wash represents the normally dry wash type named in the impact statement. Little Chino Valley and the Verde River extend the drainage network beyond the immediate Prescott core.

The bulletin also separately named recreation areas and campgrounds: Acker Park, AC Williams Granite Creek Park and Watson Lake Park. Those three sites overlap the community park list, underscoring that outdoor recreation ground was inside the flood footprint.

Households with property near any of those seven named waterways needed to keep people, pets, vehicles and portable gear away from banks and low crossings until after the 4:45 AM MST expiration and until water visibly receded.

Separate Paria River warning extended to evening in Coconino County

A second bulletin from NWS Flagstaff AZ extended the flash flood warning for the Paria River in Coconino County in north central Arizona until 5:00 PM MST / 6:00 PM MDT. The extension notice was labeled FFWFGZ.

At 12:44 PM MST / 1:44 PM MDT, a river gauge on the Paria River at Lees Ferry reported a rapid rise of 6 feet from heavy rain over the Paria River around 10 AM MST. Water levels were falling, but flash flooding was described as ongoing.

The listed hazard was life-threatening flash flooding, with heavy rain producing flash flooding in and around the Paria River. The listed source was river gauge reported. The listed impact was life-threatening flash flooding of areas in and around the Paria River.

Locations named as experiencing flash flooding were Paria Canyon, Paria River Slot Canyon and Lees Ferry. The bulletin also included the Colorado River near mile marker 0. It listed the Lees Ferry Camp Site among recreation areas and campgrounds. It listed the Colorado River and Paria River among creeks, washes and rivers.

The Paria bulletin issued direct protective instructions. It said to get out of the Paria River slot canyon. It said to get out of washes and creeks if camping or hiking. It stated that flooding is occurring or imminent and will inundate creeks and washes.

What households should do during a gauge-based flash flood warning

Move away from slot canyons, washes, creeks and low campsites when a warning names those features. The Paria River bulletin directed people to leave the slot canyon and to leave washes and creeks while camping or hiking.

Avoid dirt routes that can turn muddy and impassable. The Yavapai bulletin stated that some dirt roads will become muddy and impassable. Do not assume a familiar dirt shortcut remains usable during the warning.

Treat paved roads and underpasses as potential water traps. The Yavapai bulletin stated that paved roads and underpasses could become flooded. A route that includes State Route 69 near mile marker 296, State Route 89 between mile markers 310 and 320, or State Route 89A between mile markers 318 and 319 deserved extra caution during the stated warning period.

Keep children, pets and vehicles away from creek banks, normally dry washes, urban drainage channels, streets and underpasses listed in the impact statement. The hazard in both Arizona bulletins was characterized as life-threatening, and both cited river gauge reports rather than visual confirmation alone.