Nevada, 2018

Flash Flooding and Dense Fog in Nevada, January 9 to 10, 2018

January 9 to 10, 2018 · NWS VEF · 6 events in 2 counties and zones

A slow moving low pressure system pulled a plume of moisture over the Mojave Desert, resulting in unseasonably heavy rain and some flash flooding. The unusually humid conditions also led to patchy dense fog.

Where it happened

Every event with a place to put it; 3 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.

  • Tornadoes
  • Tropical storms and surge
  • Floods
  • Wind
  • Hail
  • Winter weather
  • Heat and drought
  • Cold
  • Fire, smoke and dust
  • Marine and coastal
  • Other

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The toll

Deaths
1
Injuries
0
Property damage
$3,000
Crop damage
None recorded
Events
6

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.

What happened

The episode as NWS VEF wrote it up.

A slow moving low pressure system pulled a plume of moisture over the Mojave Desert, resulting in unseasonably heavy rain and some flash flooding. The unusually humid conditions also led to patchy dense fog.

What forecasters said that day

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 Jan 9, 3:55 AM PST, 4 hours 20 minutes earlier.

Area forecast discussion, Jan 9, 3:55 AM PST, 4 hours 20 minutes before
Area Forecast Discussion
National Weather Service Las Vegas NV
355 AM PST Tue Jan 9 2018

.SYNOPSIS...A potent Pacific storm system will move through the
region today and this evening bringing widespread rain and high
elevation snow to the area. A few showers may linger Wednesday
across eastern Lincoln and northern Mohave Counties then dry and
mild conditions are expected Thursday through the weekend.
&&

.SHORT TERM...through Wednesday.

The upper low was approaching the California coast early this
morning and has been generating a persistent area of light to
moderate rain across mainly San Bernardino, Clark and Mohave
Counties. As of 3 am, it appeared as though the snow level was still
roughly around 9000 feet. This area of precipitation will continue
to progress northeast through the morning while the next area of
significant precipitation just ahead of the upper low pushes into
the western portion of the forecast area. Still expecting this area
of precipitation to progress from west to east across the area late
this morning through this evening as the upper low moves to the
NV/AZ border area. Snow levels should fall significantly this
afternoon and evening and the current Winter Storm Warnings remain
in effect. Most of southeast California and southern Nevada will see
precipitation chances decrease significantly as the evening
progresses but there is still a good possibility of decent
precipitation across Mohave County and eastern Lincoln County
through about midnight. Precipitation chances will linger overnight
and into Wednesday across eastern Lincoln and northern Mohave
Counties with dry conditions and warming temperatures elsewhere.

.LONG TERM...Wednesday Night through Monday.

A dry northwest flow will be over the area Wednesday night behind
the exiting storm system. High pressure is then forecast over the
region Thursday through Monday leading to dry conditions and above
normal temperatures. This pattern will also result in some breezy
north winds down the Colorado River, with the strongest winds
expected on Saturday.
&&

.AVIATION...For McCarran...Shower activity will continue this
morning until a lull between 17-19Z. Thereafter, a more pronounced
band of precip is expected to move across the valley between 21-00Z
this afternoon with more intense rainfall rates reducing vsbys to 3-
5SM at times. Continued OVC skies between 7-9 kft will prevail
through much of today before CIGs increase by 07-09Z tonight. Fairly
light winds are expected through the period. Some instability in the
atmosphere may trigger a few claps of thunder and lightning this
afternoon with the healthier precip band.

For the rest of southern Nevada, northwest Arizona and southeast
California...Scattered rain chances and fairly light winds will
continue across the region. BKN-OVC skies with continue today and
tomorrow with CIGs dropping down to 5-7 kft with increased precip
chances. Current rain band will continue to bring light rain across
NV/AZ sites this morning with a lull between 17-19Z. Thereafter, a
more pronounced band of precip is expected to move across the region
from west to east between 20-00Z this afternoon with more intense
rainfall rates reducing vsbys to 3-5SM at times. Some instability
across the CA/AZ broader may trigger a few claps of thunder and
lightning this afternoon potentially impacting the Las Vegas Valley
and river valley sites. &&

.SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report
impacts such as rainfall, snowfall, snow level, visibility, and any
other local impacts according to standard operating procedures.
&&

SHORT TERM/LONG TERM...Harrison
AVIATION...Kryston

For more forecast information...see us on our webpage:

http://weather.gov/lasvegas or follow us on Facebook and Twitter

The radar

The Las Vegas radar (KESX), 47 km away, was scanning. The volume nearest the first event began at 16:15 UTC.

Open the radar archive at this moment

Event by event

3 flash flood, 2 dense fog, 1 cold/wind chill. Local standard time, as filed.

Flash Flood, Clark

When
January 9, 8:15 AM PST to 10:00 AM PST
Where
Clark County, 1.5 mi ESE of East Las Vegas to 1.52 mi ESE of East Las Vegas
Cause
Heavy Rain
Property damage
$1,000
Reported by
County Official
Coordinates
36.108, -115.047

Stephanie Street was closed at Monson Channel due to flooding.

Flash Flood, Clark

When
January 9, 8:45 AM PST to 11:00 AM PST
Where
Clark County, 3.37 mi NW of Moapa to 3.13 mi NW of Moapa
Cause
Heavy Rain
Property damage
$1,000
Reported by
County Official
Coordinates
36.703, -114.674

Ranch Road was closed south of Highway 168 due to flooding.

Flash Flood, Clark

When
January 9, 9:16 AM PST to 3:30 PM PST
Where
Clark County, 1.68 mi ESE of Wann to 1.77 mi SW of (Lsv)nellis Afb Las
Cause
Heavy Rain
Property damage
$1,000
Reported by
Department of Highways
Coordinates
36.218, -115.094

Cheyenne Ave. was closed at and east of Las Vegas Blvd. due to flooding.

Dense Fog, Las Vegas Valley

When
January 9, 11:41 AM PST to 12:30 PM PST
Where
Las Vegas Valley forecast zone
Reported by
AWOS
Coordinates
36.215, -115.014 (the zone’s center; the record gives no point)

KHND (Henderson Airport) and a trained spotter near Green Valley Pkwy and Horizon Ridge both reported visibility less than a quarter of a mile.

Dense Fog, Las Vegas Valley

When
January 10, 4:51 AM PST to 7:32 AM PST
Where
Las Vegas Valley forecast zone
Reported by
ASOS
Coordinates
36.215, -115.014 (the zone’s center; the record gives no point)

KLSV (Nellis AFB) reported visibility less than a quarter of a mile from 0451 to 0557 PST and again from 0716 to 0732 PST.

Cold/Wind Chill, Las Vegas Valley

When
January 10, 12:00 PM PST
Where
Las Vegas Valley forecast zone
Deaths
1 direct, 0 indirect
Reported by
County Official
Coordinates
36.215, -115.014 (the zone’s center; the record gives no point)

One man died of hypothermia in Las Vegas.

The people who died

As the offices recorded each death: direct deaths were caused by the weather itself, indirect ones by something it set in motion.

EventDateAgeSexWhereKind
Cold/Wind Chill, Las Vegas Valley2018-01-1059MaleVehicle/Towed TrailerDirect

What these are

Flash Flood
Flooding that begins within six hours of the rain that causes it, or of a dam or levee failure or ice jam release, often with deadly speed.
Dense Fog
Fog reducing visibility to a quarter mile or less, filed where it caused accidents or disruption.
Cold/Wind Chill
Cold or wind chill below warning criteria that caused deaths, injuries or damage.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

More

Every storm in Nevada in 2018Every state in 2018This day in weather historyWarnings in Nevada, January 2018

Sources

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: 729175, 729188, 729193, 729200, 729202, 735911.