As high pressure responsible for excessive heat began to weaken, monsoon moisture seeped into the Mojave Desert, fueling a round of thunderstorms. Severe winds and flash flooding 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 and flash flooding 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, 11:16 AM PST, 7 hours 5 minutes 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
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LAS VEGAS NV
434 PM PDT SUN AUG 29 2021
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0418 PM FLASH FLOOD 2 NE HUALAPAI PEAK 35.09N 113.88W
08/29/2021 MOHAVE AZ EMERGENCY MNGR
EMERGENCY MANAGERS REPORTED DANGEROUS
FLOODING OVER FLAG MINE ROAD AT HUALAPAI
MOUNTAIN PARK. THE ROAD IS CLOSED.
&&
VARIANPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LAS VEGAS NV
550 PM PDT SUN AUG 29 2021
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0328 PM TORNADO 2 SSE NEW KINGMAN-BUTLE 35.23N 114.01W
08/29/2021 MOHAVE AZ PUBLIC
A LANDSPOUT TORNADO TOUCHED DOWN IN KINGMAN
NEAR STATE ROUTE 66 NORTH OF INTERSTATE 40.
NO DAMAGE OR INJURIES REPORTED. LANDSPOUT
CONFIRMED BY PHOTOS FROM THE PUBLIC.
DURATION UNKNOWN.
0549 PM TSTM WND GST 1 ENE YUCCA 34.88N 114.13W
08/29/2021 M58 MPH MOHAVE AZ MESONET
YUCCA CWOP MEASURED GUSTS TO 58 MPH
BEGINNING AT 1724 AND ENDING AT 1733.
&&
VARIANPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LAS VEGAS NV
558 PM PDT SUN AUG 29 2021
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0317 PM TSTM WND DMG 1 SW DOLAN SPRINGS 35.58N 114.28W
08/29/2021 MOHAVE AZ PUBLIC
13 POWER POLES SNAPPED IN DOLAN SPRINGS ON
PIERCE FERRY ROAD FROM SEVERE THUNDERSTORM
WIND GUSTS. POWER OUTAGES CONFIRMED BY LOCAL
POWER COMPANY. A 5TH WHEEL RV TIPPED OVER.
NO INJURIES REPORTED.
&&
VARIANThe Las Vegas radar (KESX), 129 km away, was scanning. The volume nearest the first event began at 02:21 UTC.
4 flash flood, 1 thunderstorm wind. Local standard time, as filed.
Thirty low water crossings on Highway 95 between Needles and Havasu Lake Road were covered in mud and debris.
Nipton Road was flooded east of Ivanpah Road.
The Nipton Road off ramp from Interstate 15 was flooded, and vehicles were stuck.
Indian Trail Road was damaged by flooding between Adobe Road and Mesquite Springs Road.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in California in 2021Every state in 2021This day in weather historyWarnings in California, 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: 981300, 981301, 981302, 981305, 981306.