A flash flood warning for parts of Gila and Maricopa counties, including Rio Verde, runs until 10:30 a.m. MST Sunday. Issued at 7:26 a.m. MST, it describes life-threatening flash flooding with a considerable damage threat. Radar indicated 0.5 to 1 inch of rain, with flooding ongoing or expected shortly. The National Weather Service warns against crossing flooded roads.
An atmospheric river is pouring heavy rain onto already soaked ground across Arizona, southern Utah and southwest Colorado on Sunday, and forecasters expect numerous flash floods through Monday morning. The National Weather Service's Weather Prediction Center has a Moderate Risk of excessive rainfall, level 3 of 4, for parts of the Four Corners region, and flood watches cover the Phoenix area, the Lake Mead and Lake Havasu area, the Grand Canyon, and Zion and Bryce Canyon national parks.
The Associated Press reported that crews rescued people from flooded vehicles in Arizona and Nevada on Friday.
Where the risk is highest
The heaviest rain is expected along the Mogollon Rim north and east of Phoenix, where the prediction center's Sunday morning discussion calls for a widespread 3 to 5 inches. Rainfall there has a 70% to 90% chance of exceeding amounts expected once every 100 years, the center said, which is generally the threshold for its top category, High Risk. It held off on that for now because the moisture is moving quickly and the atmosphere lacks instability. A second Moderate Risk area covers the San Juan Mountains of southwest Colorado, which flooded last week.
After a long wet period across the Southwest, the ground is saturated, so "all of today's rains will be converting to runoff," forecasters wrote. Normally dry washes, slot canyons and areas burned by wildfires face the highest risk.
Flood watches and warnings in effect
These are the main National Weather Service alerts in effect early Sunday. Times are local.
| Area | Alert | Until | Expected rain |
|---|---|---|---|
| Phoenix metro, rural Maricopa County, northwest Pinal County | Flood watch | Late Sunday night | 1 to 2 more inches |
| Northern and central Arizona, including the Grand Canyon | Flood watch | Late Sunday night | 1 to 4 more inches |
| Lake Mead, Lake Mohave, Lake Havasu, northeast Clark County, Nev. | Flood watch | Late Sunday night | Half an inch to an inch |
| Southern Utah, including Zion, Bryce Canyon, Capitol Reef and Lake Powell | Flood watch | Sunday evening | Moderate to heavy |
| Southeast Utah and southwest Colorado | Flood watch | Monday morning | 1 to 3 inches |
| Western Pima County, Ariz. | Flood watch | Late Sunday night | Half an inch to an inch, locally 1.5 |
Creeks and washes already flooding
Separate warnings address flooding that has already started:
- Near Sedona, the weather service forecasts Oak Creek at Cornville to crest at 11.91 feet around 8 p.m. Sunday, nearly 4 feet above its 8-foot flood stage. A warning covers Coconino and Yavapai counties until 2 p.m., where 1 to 2.25 inches had fallen by early Sunday.
- Along the Verde River between Bartlett Lake and the Salt River, flooding threatens low-water crossings and recreation. A warning covering Rio Verde and Fort McDowell runs until 8 a.m. MST Monday.
- On Tonto Creek, the weather service directs all creek-crossing traffic to the Tonto Creek Bridge and says Bar X and other low-water crossings will be impassable. That warning runs until 8 a.m. MST Monday.
- At Vamori Wash in Pima County, the Highway 21 bridge approaches may be impassable once the wash tops 9.8 feet; it stood at 9.5 feet early Sunday.
- In Garfield and Kane counties in Utah, flooding is expected around Bryce Canyon National Park, Kodachrome Basin State Park, the Paria River, Buckskin Gulch and Wire Pass until 4:45 p.m.
If you are heading to a park or canyon
The weather service's Flagstaff office advises changing plans to hike, boat or paddleboard in slot canyons or normally dry washes, and checking in at a visitor center or ranger station before any trip. Utah forecasters warn that washes and streams can turn dangerous within minutes, even from distant rainfall.
At the Grand Canyon, the park's hiking closure notice, updated October 27, lists the North Kaibab Trail and Phantom Ranch as closed after the August 29 flash flood. It gives no estimated reopening date.
Drivers should turn around at flooded crossings; most flood deaths happen in vehicles, the weather service says. The Flagstaff office also advises having a way to receive flash flood warnings.
Our Halloween forecast covered the start of this wet stretch.
