National Weather Service issues flash flood warning, hazardous weather outlook

Stock Image, St. George News

NOTE: This page will be updated periodically to new weather alerts and information as they emerge.

ST. GEORGE —The National Weather Service has issued both a flash flood warning for northwest Arizona and southern Nevada, as well as a hazardous weather outlook for the western two-thirds of Utah for the next seven days.

Flash flood warning

Scattered thunderstorms capable of producing intense rainfall that could lead to flash flooding in normally dry washes, low water crossings and poorly drained intersections is expected through Thursday evening. Be especially cautious at night when flash flood danger may be harder to see.

A flash flood warning has been issued for parts of Nevada and Arizona including Clark County and Mohave County, Aug. 3, 2017 | Map courtesy of the National Weather Service, St. George News | Click to enlarge


At 8:50 a.m. Thursday Doppler radar indicated scattered thunderstorm producing heavy rain over portions of northwest Arizona that include Lake Havasu and Fort Mohave, Lake Mead National Recreation Area, northwest deserts and Northwest Plateau.


Affected areas in southern Nevada include Lake Mead National Recreation Area, Las Vegas Valley, northeast Clark County, Sheep Range, southern Clark County, Spring Mountains-Red Rock Canyon and western Clark County, northwest deserts and southern Nye County.

Hazardous weather outlook

The hazardous weather outlook covers southwestern Wyoming and the western two-thirds of Utah, including west central Utah, southwest Utah, Utah’s Dixie and Zion National Park, south central Utah, Glen Canyon Recreation Area/Lake Powell and central and southern mountains.

Day one: Thursday

Scattered showers and thunderstorms are expected across the southern outlook area. Most of these will remain over the higher terrain and across extreme southern Utah. Locally heavy rains are possible with the showers and storms across the far south.

Days two through seven: Friday through Wednesday

The coverage of showers and storms will stay about the same on Friday with a continued chance of locally heavy rains across the far south. Thunderstorm coverage should increase this weekend and
continue into early next week with the threat of heavy rainfall spreading across more of the outlook area.

This will bring a risk of isolated flash flooding of slot canyons, dry washes and burn scars.

Read more: This is how monsoons could menace communities around the Brian Head burn scar

Precautionary preparedness actions

“Turn around, don’t drown” when encountering flooded roads. Most flood deaths occur in vehicles.

Remain alert for flooding even in locations not receiving rain. Dry washes, streams and rivers can become flooded with raging killer currents in a matter of minutes, even from distant rainfall.

Closely monitor weather forecasts and be prepared to take immediate action should heavy rain and flooding occur or a flash flood warning is issued.

The National Oceanic and Atmospheric Association and the National Weather Service safety tips for flash flooding:

  • Flash flood waves move at incredible speeds and can roll boulders, tear out trees, destroy buildings and bridges and scour out new channels. Killing walls of water can reach heights of 10 to 20 feet. You will not always have warning that these deadly, sudden floods are coming. When a flash flood warning is issued for your area or the moment you first realize that a flash flood is imminent, act quickly to save yourself. You may have only seconds.
  • Most flood deaths occur in automobiles. Do not drive your vehicle into areas where the water covers the roadway. Flood waters are usually deeper than they appear. The road bed may not be intact under the water. Just one foot of flowing water is powerful enough to sweep vehicles off the road. If the vehicle stalls, abandon it immediately and seek higher ground. Rapidly rising water may engulf the vehicle and its occupants and sweep them away.
  • Do not hike rivers and especially slot canyons while flash flood warnings are in place.
  • Do not hike alone and always tell someone where your group is going.
  • Get out of areas subject to flooding, including dips, low spots, canyons and washes.
  • Avoid already flooded and high velocity flow areas. Do not try to cross a flowing stream on foot where water is above your knees.
  • Be especially cautious at night when it is harder to recognize flood dangers.
  • Do not camp or park your vehicle along streams and washes, particularly during threatening conditions.

During any flood emergency, stay tuned to your NOAA weather radio, commercial radio or television. Follow St. George News at and St. George News Facebook for weather alerts and updates relevant to the affected areas. Information from the National Weather Service and disaster and emergency services may save your life.

Email: [email protected]

Twitter: @STGnews

Copyright St. George News, LLC, 2017, all rights reserved.


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  • Foxyheart August 3, 2017 at 1:02 pm

    Lol, it always amazes me how the weather has definite boundaries. I notice it will only follow the state line at Arizona, not coming into Utah at all…..

    • DB August 3, 2017 at 4:41 pm

      I’ve wondered the exact same thing myself. Also, there’s been a ’20 percent’ chance of rain for days. I think it’s code telling us that they really don’t have a clue…Look out the window and make your own assessment.

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