As high pressure responsible for excessive heat began to weaken, monsoon moisture seeped into the Mojave Desert, fueling a round of thunderstorms. Severe winds, flash flooding, and a landspout occurred.
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Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS VEF wrote it up.
As high pressure responsible for excessive heat began to weaken, monsoon moisture seeped into the Mojave Desert, fueling a round of thunderstorms. Severe winds, flash flooding, and a landspout occurred.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Las Vegas, NV wrote its last area forecast discussion before the first event at Aug 29, 12:16 PM MST, 3 hours 1 minute earlier.
Area Forecast Discussion National Weather Service Las Vegas NV 1216 PM PDT Sun Aug 29 2021 .SYNOPSIS...Hot temperatures and isolated thunderstorms are expected through Monday with Excessive Heat Warnings in effect for much of the region. Moisture will be increasing through the middle of next week aided by the remnants of Nora. This moisture will lead to better chances for shower and thunderstorm activity in Mohave County today, expanding west and north into southern Nevada through mid-week. && .DISCUSSION...Through next Sunday. Typical monsoon pattern expected with storms firing over the higher terrain of Clark, Mohave and San Bernardino Counties into this evening and again Monday afternoon/evening. Gusty outflow winds and brief heavy rain main concern with storms. Did blend in a higher percentage of the camPoPs for the rest of today through Monday. Above normal temperatures persist with an excessive heat warning covering parts of our area through Monday evening. Tuesday afternoon through Wednesday still looks to be our most favorable period for showers and thunderstorms as additional dynamics come into play. Models all show a weak disturbance situated near 30N/120W early Tuesday morning. Stronger trough entering the Pac NW poised to draw this feature inland across the area late Tuesday afternoon through Wednesday. Developing jet streak and associated divergence aloft will provide some additional lift. As for models. GFS and its ensemble members continue to support a wetter scenario for southern Nevada and eastern California with highest QPF values still plotted across northwest Arizona. Believe latest NAM and EC and its members continue to underplay the situation as associated dynamics will be overspreading PW values between 1" and 1.5". WPC Day 3 QPF (5 pm Tue - 5 pm Wed) depicting 0.50"-1.25" for the eastern half of Mohave County. The Colorado River Valley, southern Nevada and eastern California mostly a 0.50" or less. No hydro headlines will be issued with this package as discussed in a collaboration call with WPC and AZ offices. Residual moisture Wednesday night and Thursday will keep additional chances for showers and thunderstorms largely confined to Mohave County, but can not rule out a few storms lingering over eastern Nevada. Mainly dry conditions with temperatures near normal Friday into the Labor Day Weekend. The exception is in Mohave County where lingering moisture could still ignite a few showers and thunderstorms. && .AVIATION...For McCarran...Light winds favoring an easterly direction will remain before giving way to some southeasterly winds this afternoon around 22-23Z. Expect winds around 10-12 knots with some occasional gusts around 15-20 knots lasting through 01-02Z. Thereafter, winds will shift to more of a south-southwest direction, eventually becoming light and variable overnight. Low confidence, but there is a very small chance for an isolated storm to develop just south of the Las Vegas Valley along the McCullough Range which may bring lightning within 15 miles of KHND. Not anticipating any storms to develop in the Las Vegas proper this afternoon, but will be possible tomorrow afternoon. Some FEW to SCT aoa 12 Kft is expected, primarily along the higher terrain this afternoon with more cloud cover possible tomorrow. For the rest of southern Nevada, northwest Arizona and southeast California...Isolated to scattered thunderstorms are possible later this afternoon and again tomorrow across southeastern portions of our region, including in and around the Colorado River Valley. Low confidence on storms impacting KIFP and KEED directly, but vicinity thunderstorms maybe within 15 miles at times both afternoons. Main concern would be strong outflow winds impacting the terminals, potentially bringing gusts up to 30-40 knots. FEW to SCT aoa 12 Kft will be possible in this region. Further north and west, expect light winds following typical wind patterns. Skies will be mostly clear with some FEW aoa 12 Kft across some of the higher terrain in the western Mojave Desert. Although, haze from distant wildfire smoke will reduce slant range visibility at times, especially across the Sierra, western Mojave Desert and parts of the southern Great Basin. Less confident on the potential for smoke/haze to impact KBIH tonight, with some signal of smoke coming in from the north-northeast, the smoke may not make it to the Owens Valley overnight tonight. If it does, the HRRR Smoke indicates it may be more dense, dropping vsbys to around 4-5 SM. && .SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report any significant weather or impacts according to standard operating procedures. && DISCUSSION...Pierce AVIATION...Peters For more forecast information...see us on our webpage: https://weather.gov/lasvegas or follow us on Facebook and Twitter
The Las Vegas radar (KESX), 57 km away, was scanning. The volume nearest the first event began at 22:19 UTC.
6 flash flood, 3 thunderstorm wind, 1 strong wind. Local standard time, as filed.
Thirteen power poles were snapped on Pierce Ferry Road in Dolan Springs, and a fifth-wheel RV was blown over.
Landspout. Location: 35.229N 114.009W. A landspout touched down in open desert between neighborhoods. No damage occurred.
Flag Mine Road was closed due to flooding.
Signal Road was closed from Highway 93 to Alamo Road due to flooding.
Bogeles Ranch Road was closed from Upper Trout Creek Road to Bogeles Ranch due to flooding.
Pierce Ferry Road was damaged by flooding in multiple areas between Highway 93 and mile marker 3.
Antares Road was closed from Route 66 to Pierce Ferry Road due to flooding.
Two to two and a half feet of water flowed over DW Ranch Road from the Frees Wash.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Arizona in 2021Every state in 2021This day in weather historyWarnings in Arizona, August 2021
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 981288, 981289, 981290, 981291, 981292, 981294, 981296, 981297, 981298, 981299.