A big push of monsoon moisture fueled an outbreak of thunderstorms over the Desert Southwest. Many storms in the Mojave Desert produced flash flooding and severe weather.
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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.
A big push of monsoon moisture fueled an outbreak of thunderstorms over the Desert Southwest. Many storms in the Mojave Desert produced flash flooding and severe weather.
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 Jul 24, 8:15 AM PST, 2 hours 15 minutes earlier.
Area Forecast Discussion National Weather Service Las Vegas NV 915 AM PDT Mon Jul 24 2017 .SYNOPSIS...A significant push of monsoon moisture will spread northward today bring the threat of heavy rain and thunderstorms to much of the area over the next couple of days. The greatest threat will occur today and tonight and again Tuesday afternoon before a drying trend begins mid to late week. && .UPDATE...Gearing up for what is anticipated to be an active afternoon. Inverted trough lifting northward today is already kicking off strong convection near the Phoenix area and this will be approaching our region during the afternoon and evening hours. Additionally, areas west and north of the Colorado River have woken up to considerable sunshine which will aid in destabilizing the airmass ahead of this feature. This mornings 12z Las Vegas sounding sampled a precipitable water value of 1.59" which sets a new daily record, and given the active afternoon expected we will be releasing a 18z sounding to better sample the afternoon airmass before storms develop. Made some minor updates to the forecast mainly to tweak PoPs for ongoing trends and anticipated afternoon development. Otherwise, the forecast is in good shape. Be prepared for strong storms this afternoon and the likelihood of areas of flash flooding. -Outler- && .SHORT TERM...Today through Wednesday Been a fairly active evening over portions of the area with the main activity occuring over Lincoln County where significant rainfall fell over southern portions of the county earlier this evening. Some showers and thunderstorms did work into northern and central Clark County early this morning as there is still significant instability in place. It's likely that isolated storms will continue to generate into early this morning, but most have been short lived. As we move into the day a significant push of monsoonal moisture will surge northward. Over the past few hours Blythe, CA and Roll, AZ have seen their PW values jump to around 2.15 inches. This surge of moisture will continue to push northward today with the 2 inch PW line pushing up the Colorado River Valley and 1.5 inches over much of Mohave, Clark, and San Bernardino Counties. The main concern over the past couple of shifts has been the amount of cloud cover today to potentially limit convection. Morning satellite imagery showing partly to mostly cloudy skies over Mohave, Clark, and Lincoln Counties. It is certainly not widespread and the current thinking is that we should end up with enough sun today to help get things going. We will have plenty of instability in place and storm motions will be rather slow. Another factor is a fairly strong vort max rotating north up the Colorado River this afternoon. This area could be the main focus for convection and will likely help storms go overnight. Although it's difficult to pin point where thunderstorms will develop, felt that the threat of flash flooding was too great to not issue any watches. So, after coordination with other offices and WPC, felt that going with a Flash Flood Watch for Mohave, Clark, San Bernardino, southern Nye, and Lincoln Counties was the way to go. The product was issued from 5am this morning until 5am Tuesday morning. Depending on how much cloud cover we see Tuesday, we could see another round of showers and thunderstorms during the afternoon for much of the area as moisture and instability will remain in place. Temperatures will likely be held to below normal readings today and Tuesday due to the additional clouds and potential rain. Somewhat drier air will try and work into the region Wednesday mainly limiting convection to the northeastern sections of the CWA. .LONG TERM...Thursday through Saturday. Gradual drying and warming is expected for Thursday as weak southwest flow returns to the region. Enough moisture is likely to remain in place for afternoon showers/storms over favored high terrain. By Friday, high pressure once again pushes back to a favorable location near the Four Corners, allowing for a moist southeasterly flow into the region. However, this is where guidance begins to diverge, with the GFS keeping the high and favorable flow well into the weekend while the ECMWF is significantly different, pushing the high to near Reno and keeping much of the moisture to the south of Las Vegas. For now I've split the difference, increasing dew points, and PoPs over the area, but with a emphasis on areas south of Las Vegas. && .FIRE WEATHER...Scattered showers and thunderstorms will occur over much of the region today with any storm capable of producing very heavy rainfall. Although storms will be possible in Inyo County today, those are expected to be more isolated. However, areas of far southeastern Inyo could see more scattered storms. Conditions will gradually dry out midweek onward, with thunderstorms decreasing in coverage each day. Temperatures will be near normal to somewhat below normal through Wednesday, before returning to slightly above normal late in the week. && .HYDROLOGY... Creeks, streams and rivers in northern Inyo County have shown decreasing flows over the last couple of days. However, some road closures continue in the area. Bishop Creek Bypass and Big Pine Creek Bypass continue to be utilized to minimize flows through Bishop and Big Pine. Remember, never drive through flooded roadways or around barricades. Also, pastureland or farmland adjacent to creeks, streams or rivers could experience areas of standing water. && .AVIATION...For McCarran...East winds will occur early this morning due to outflow winds from earlier storms. Winds will generally be south to southwest around 10 kts away from any storms. Scattered showers and thunderstorms will likely occur through much of today with the greatest threat of heavy rain late afternoon and evening. Storms also have the potential to go through much of the night. Cigs to fall to as low as 6k feet near stronger storms. Otherwise cigs will mainly be AOA 10 kft. For the rest of southern Nevada, northwest Arizona and southeast California...Scattered showers and thunderstorms are expected to impact much of the region today with potentially heavy rainfall. Cigs will generally be around 10-12k feet, but could fall to as low as 5k feet in heavier storms. Winds will generally be under 10kts, but gusty and erratic near any storms. Storms could also go through tonight and into Tuesday morning. && .SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report any significant weather and especially flood impacts the next several days as an active monsoon pattern unfolds. && Short Term/Fire Weather/Aviation...Gorelow Long Term....Wolcott For more forecast information...see us on our webpage: http://weather.gov/lasvegas or follow us on Facebook and Twitter
The Las Vegas radar (KESX), 99 km away, was scanning. The volume nearest the first event began at 18:31 UTC.
6 flash flood, 1 hail. Local standard time, as filed.
A wall of water, mud, rocks, debris, and small trees flowed down Lee Canyon Wash and overwhelmed culverts. Water and debris closed Highway 156 near mile marker 2.
Water, rocks, and debris flowed over Highway 93 and many secondary roads in Pioche, and roads in Caselton were damaged by flooding.
The intersection of Lyman Street and Bert Circle was flooded and closed.
Water 1.5 to two feet deep ran through the streets of the Elk Ridge subdivision, and debris washed onto Maggie Road.
Nipton Road was closed in both directions near Searchlight, and Cottonwood Cove Road was closed due to extensive flooding.
Water two to three feet deep damaged Highway 375 3 miles NW of Rachel, and water got into basements of two residences in Rachel.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Nevada in 2017Every state in 2017This day in weather historyWarnings in Nevada, July 2017
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: 709573, 709574, 709575, 709576, 709577, 709578, 709579.